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Hello, my name is Cardio, short for Cardiovascular. Before anyone slams himself in the head with the heaviest dumbbell and destroys the next piece of strength or cardio equipment, you might want to take a Xanax and chill out. I'm quite aware that the overwhelming majority of those in the fitness community, including competitors, coaches and strength athletes, have a love/hate relationship with me or flat out hate my guts and wish I would stop making their lives a living hell (or so it seems).
I wanted to provide everyone with some actual knowledge about me because a large cohort of you mistakenly blame me for aspects of your training that are, frankly, not my fault but perhaps the fault of your own uneducated self. The information presented in this article isn't an intentional jab at any given person or groups of individuals but merely serves as an educational yet informative piece about the history of me. Because I don’t have a last name, just call me Cardio.
I agree. I'm found in nearly every single small and large big box gym in the country as well as in semi-private facilities and strength and conditioning facilities. I usually sit on my ass until a client or athlete decides to use me, and aside from that, I take up too much space because there are way too many versions of me that most people either grossly overuse or don’t know the correct context of how I can actually help them. Although a broad definition, I'm more commonly used to describe the cardiovascular system (also referred to as the circulatory system), which comprises the heart and blood vessels that carry nutrients and oxygen to the body's tissues and eliminates carbon dioxide and other waste materials (3, 5, 18). In fact, my history dates back to the second century AD in Rome. The Greek physician Galen observed that blood vessels carried blood and identified venous (dark red) and arterial (brighter and thinner) blood, each with distinct and separate functions, and William H*****, in the early 1600s, initially pioneered our current conceptualization and current understanding of heart beats and blood flow (35).
How Do I Work
The scientific effects of my impact have consistently focused on health benefits such as with the prevention of diseases including coronary heart disease, type 2 diabetes, hypertension, some cancers and other chronic diseases (20, 21, 36). Other aspects of my research have examined my effect with exercise in reducing stress, depression and anxiety (1). When I’m activated, my cardiovascular effects of exercise performance are centered on heart rate, stroke volume (the amount of blood pumped per beat) and heart contractility (forcefulness of each heart contraction). Collectively, these variables increase blood flow and oxygen supply to meet the demands of exercise training. The contraction of the skeletal muscle also increases venous blood flow return to the heart, which increases ventricle blood filling (called preload and not the stimulant kind in case you’re wondering). This boosted preload contributes to my heart's increased stroke volume during exercise, which is a major determinant of aerobic performance (17).
Brain circulatory system
A wide variety of my structural adaptations are common with progressively increasing amounts of doing my type of training. These adaptations include thickening of the heart muscle and increased left ventricle size, contributing to improved heart function during exercise. Additional adaptations that I provide (17, 28, 29) include the following:
Increased cardiac muscle mass
Increased stroke volume
Disposal of metabolic wastes
Increased oxidative enzymes
Faster diffusion rates of oxygen and fuel into muscle
Increased left ventricle and chamber volume
Increased carbohydrate sparing (thus greater use for fat as fuel)
Increased number of mitochondria
Enhanced fat oxidation (HIIT as well)
Increased expression of fatigue resistant slow twitch muscle fibers
It’s helpful to know that I come in many different shapes and sizes. Specifically, there are numerous training modes to choose from (you know cardiovascular and aerobic fitness), and they all have different outcomes. Considering the overwhelming majority think and believe that I’m a one size fits all approach, allow me to retort some examples:
Type 1, High Intensity Aerobic Interval Training: High intensity aerobic interval training, referred to as a HIT or HIIT programs, are executed by many coaches and trainers. These workouts are described as a compromise between sustained, moderate intensity training and sprint interval training. From the science, I show that the cardiovascular adaptations to HIIT are similar to, and in some cases superior to, those of continuous endurance training (10, 11, 14, 26, 39). Increased mitochondria size and number is something my system now provides you. This has become a hallmark adaptation to HIIT (12). Bet you didn’t know that, huh?
Type 2, Sprint Interval Training: If you aren't performing my sprints via Prowler work, hill sprints or something that directly relates to me in this area, you don’t deserve any cardiovascular adaptations and gains. I'm an all-out cardiovascular effort lasting several seconds to less than two minutes. Research demonstrates that short duration SIT training produces similar cellular fat metabolism adaptations comparable to traditional endurance programs (4).
Type 3, Tabata Style Intervals: Tabata and I go way back. Tabata-style training can use any number of my cardiovascular equipment such as the treadmill, rowing machine or stationary bike or in calisthenics such as burpees, mountain climbers or body weight squats (or even with dumbbells or kettlebells). Tabata is the use of, for example, 20 seconds of high intensity work followed by 10 seconds of rest repeated up to eight times. During the rest interval (i.e. three minutes), the exerciser (you) continues to move to avoid blood pooling in the lower extremities. These training sessions usually last around 25 minutes and have been shown to be effective at improving VO2 max (23, 26, 34, 39).
Type 4, Metabolic Resistance Training: A very popular and highly effective method of me is metabolic resistance training (MRT). This refers to exercise training sessions designed to maximize caloric expenditure and increase the metabolic rate. The main stimulus for metabolic resistance training is to use movement-based exercises or exercise that incorporates larger muscle mass. A benefit of this type of me is do more work in less time or increase exercise density. Specifically, you want to do high reps (i.e. 15) that elicit greater volumes of energy than the higher intensity lifts (over 85 percent) and limit the rest intervals to 30–40 seconds or less per set, which yields a better training density and more work in less time. Surprisingly, little science has been done on me with this training, and although many methods and variations work, evidence-based science guidelines are still lacking, which make me a little sad, but I’m optimistic.
2015-06-26 18.54.20
Why Do Peeps Hate Me So Much?
This is the million-dollar question that everybody wants to know. Over the last few years, coaches, trainers and numerous bodybuilding and fitness competitors have become very outspoken regarding the effects I produce throughout various types of training. Specifically, if you do me (pun intended), I will somehow make you fat. While some information is entertaining and laughable, the majority of it is misleading and an eager attempt to create either online celebrity fitness status or simply a paucity of proper education that perpetuates additional uninformed trainees. Perhaps these are the same people who believe that all calories are created equal and that Anna Nicole married for love!
Why have I been so outlawed by so many in the industry? When did performing my type of sessions suddenly become “badmouthed ” and create the “cardio haters” private only club? Do you know how many scientific studies have been completed for my type of training? It’s thousands! Yes, I said thousands! What about performing my cardio training on measuring body fat? If you cross reference on PubMed ‘aerobic’ with ‘body composition,’ you will clearly be shown over 500 publications and that barely touches resistance training. Further, which version of “cardio" are you incorporating?
Let’s a take a minute to go back in time to the learning tree, shall we? Most people, including average gym goers and even those in competitive strength sports, view “me” as something for endurance and marathon and cycling aficionados who are less physically impressive and have little muscle mass. While this is true for many, let’s start with some actual scientific facts about me.
Going back to the 1980s, 12 weeks of doing some of my wonderful aerobic dance training (three days per week for 45 minutes) resulted in significant increases in lean body mass and body density coupled with decreases in the percentage of body fat and the sum of four skin-fold thicknesses (37). Recently, researchers put 28 obese children (16 boys and 12 girls, aged 12–14 years) into an exercise group or control group. Once again, the exercise group participated in 16 weeks of my aerobic exercise program (ya know, the one you hate) for four, 60-minute sessions per week at 70–85 percent of heart rate max) in addition to the school’s own physical education. Those kids who completed my aerobic exercise not only yielded a smaller waistline, but they also showed a significant drop in fat mass (30).
RELATED: Cardio in the Off-Season: Make Up Your Mind
Another recent study determined the effect of cardiovascular exercise (oops, I said it again) without energy restriction on weight loss in sedentary, overweight and obese men and women. Subjects were randomized into a 400 calorie/session group, a 600 calorie/session group or a non-exercise control group. Exercise was supervised for five days/week for 10 months. Isn’t it awesome to have science that can dispel witchcraft? Guess what they found? They found that “significant changes in percent body fat over 10 months were observed in both the 400 (- 2.9 percent) and 600 (-4.4 percent) kcal/session groups. Percent fat was unchanged in the control group (-0.6 percent), but the reductions in body weight observed in both exercise groups were a result of decreased fat mass and preservation or increase in fat-free mass.” (8).
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I can’t believe it. Holy crap I actually worked! The group that performed my type of exercise actually lost body weight and fat? Say it isn’t so? Here is the hardcore truth about me—if performing me truly made you fat, why are endurance athletes consistently lean? Some of you will throw the genetics card in my face, but so what? There is a reason this phenomenon occurs. I’ll let you marinate on that for a while. What about volleyball players? They perform me and boxers, too, and a multitude of other sports. Haters gonna hate!
What Are My Effects on Muscle?
It has been known for quite some time that performing too much of me may promote a loss of lean body mass, especially for those wanting more muscle mass. But listen people, that’s not the same as saying ‘cardio makes you fat.’ Oftentimes, this is referred to as “concurrent training or the “interference phenomenon.”
The question often asked is whether performing my particular type of exercise prior to strength training or after will compromise your strength training performance? In other words, will I compromise your gains, bro?
Early research completed on me showed that concurrent training demonstrated that strength improvements are impaired prior to performing my cardiovascular exercise (9, 15) while other studies during this time on concurrent training showed no impairments (24, 31). Interestingly, some science performed on my concurrent training may actually increase muscle mass gain (13, 38). Further (don’t you love science?), the anabolic response to resistance exercise was decreased when preceded by endurance training. Meaning, doing my cardio after trying to get swole patrol increased protein degradation (6) while a recent study showed no significance (22). Lastly (I’m not finished yet), if you discuss the actual training adaptations, research conducted on me (cardio) have shown that doing me (pun intended again) first or last is essentially insignificant (7, 22, 25). If I keep going with this and as you may have guessed, the interference with strength and muscle size gains tend to be reduced if cardio sessions aren't too frequent or of excessive duration (16, 38).
Although a different topic entirely, the key with doing me (yes, I said it again) is to figure out how to do the least amount of volume of me possible to improve performance while also attaining the necessary result. Let’s be clear, this is not an anti-cardio segment on CNN. There are numerous athletes or so called “hybrid athletes” who engage in different athletic disciplines and don't obviously support one type of training or another, such as those competing in powerlifting and endurance competitions. Such athleticism should serve as a good model for those who think that performing me (cardio) will make you small, weak, glycogen depleted and, well, fat (so they say). Sure, performing too much of me (aerobic training) may decrease muscle mass, but it isn't a universal prospect just in case you might go there!
However, I might as well mention dieting. Here’s the main caveat. If you use me for dieting for a physique show, it’s best to continue to adapt to the strength training. If you use me excessively, you will likely have to further decrease your energy output, which results in expending fewer calories for a given movement or training session and results in me using up your most lean tissue (muscle mass) to feed myself. Over time, you will likely over diet, continue to lose your muscle mass (because I took over your life) and your performance and overall physique won't be happy.
shrongher prowler
How Do I Impact Resistance Training and Performance?
This is probably the most misunderstood concept and application that you peeps don’t get about me. Mitochondrial respiration, or the aerobic system (also known as cardio), operates continuously and is probably the most important, both at rest and during training. It is fueled primarily on fat and glucose. It’s the only one that directly requires oxygen to function. Now, despite the fact that this energy system is ongoing, generally speaking, it’s the last system to kick in. However, in highly trained athletes, particularly endurance athletes, my system is so dominate that I actually activate much sooner compared to normal individuals, and I'm able to reach steady state much quicker compared to less trained individuals. The majority of long distance events and sports (marathon, cycling) require exceptional aerobic capacity, as do athletes in all continuous action field and team sports (i.e. soccer, basketball).
Traditionally, the belief was that the best way to develop my oxidative system was through long, slow cardio (you know, the one that people say makes you fat). Times have changed, and although many still do believe this and even though my aerobic system certainly responds well to that type of training, recent research suggests that the oxidative system also works extremely hard to help you recover after high intensity anaerobic efforts (33).
What about you meatheads? Yes I mean you, too! Due to heavy strength training’s intermittent nature, the energy expenditure contributions of weight training are almost always in a non-steady state compared to my type of aerobic exercise that is usually defined as being steady state. What does this mean? Well, a resistance training session corresponds to a series of intermittent/non-steady state waves of intensity and effort for the oxidative system (mitochondrial respiration). Many times, individuals feel “gassed” after high intensity bouts of strength training or conditioning, even though these specific bouts themselves are technically anaerobic (my alter ego). What is happening is that mitochondrial respiration (my oxidative system) moves into hyper-drive in order to replenish the depleted ATP stores and remove the buildup of metabolic byproducts that were produced from the other energy systems (phosphagen and glycolysis).
RELATED: Sprinting Problems, Prowler Solutions
Upon cessation of intense lifting or interval work, mitochondrial respiration (yes, me again) continues activity for a few days. This is where the concept and application of excess post-exercise oxygen consumption (EPOC) comes in. This occurrence can burn additional fat and calories up to 72 hours post-training when intensity and duration (especially intensity) are the presiding factors (2, 19).
Here’s the deal—unless you compete in endurance events, performing lots of long, slow cardio is not the best way to train me and enhance my system. You are better off engaging in higher intensity training as a more effective and efficient means to develop my oxidative system and drive fat burning. Lastly, because low intensity aerobic activity enhances recovery from other forms of training, perhaps the best use of oxidative training is as a recovery tool used on non-training days.
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Can You Do Me Fed or Fasted?
Traditionally, the hypothesis and rationale for doing me fasted was based on research showing that low glycogen levels cause your body to shift fuel utilization away from carbohydrates, therefore allowing greater mobilization of stored fat for energy. However, this whole debate (which still occurs) was based on short-term data. No study had actually investigated the effects of my fasted cardio on body fat when subjects were in an energy deficit in efforts to result in weight loss.
A very recent study examined the effects on doing me fed or fasted (32). Twenty young, non-obese (BMI < 30) subjects were recruited to participate in the study. Prior to the intervention, subjects were tested for body composition using a Bod Pod and then pair matched based on initial body mass measurements. Subjects were randomly assigned to one of two groups: my fasted training (FASTED) group that performed exercise after an overnight fast (n =10) or my non-fasted training (FED) group that consumed a meal prior to exercise (n =10). These meals were provided in the form of a shake, which contained 250 calories consisting of 40 g carbohydrate, 20 g protein and 0.5 g fat. Training consisted of three days a week for one hour on a treadmill. Subjects performed a five-minute warm up followed by 50 minutes of walking/jogging at 70 percent max heart rate followed by a five-minute cool down session. Subjects were provided with customized meal plans intended to result in about a 500 calorie deficit. Protein was kept high to maintain lean body mass, and subjects recorded their food via My Fitness Pal on a daily basis so that dietary intake could be monitored. Further, ongoing nutritional counseling was provided to subjects throughout the study to ensure adherence.
After four weeks, the results showed that both groups lost a statistically significant amount of weight (1.6 kg versus 1.0 kg in my FASTED versus my FED groups) and fat mass (1.1 kg versus 0.7 kg in my FASTED versus my FED groups). However, no significant differences were noted between groups in any of the body composition outcomes.
It is often considered that the true benefit of fasted cardio is specific to very lean individuals, including those genetically lean and pre-contest physique and bodybuilders. However, based on this study, there wasn't any evidence that the fasting condition conferred any benefits. However, a similar investigation showed that fat utilization over 24 hours was actually greater when eating prior to performing my fed cardio versus my fasted cardio (27). Therefore, which is better—fed or fasted? Well, my advice is to concentrate on total energy consumption and expenditure and macronutrient ratios that work for you. Whether you perform my type of cardio fasted or fed is a matter of personal preference.
What Can You Do?
As previously discussed, this was mainly written as an informative piece to educate the reader about what I actually do, with actual scientific evidence and not your average “broscience." It is in these efforts that I hope I provided you with a better understanding of my system and the diversity to which I represent. Do as you wish. If you enjoy doing me, do me. If not, don’t. Based on my applications—and there are some exceptions—the overwhelming scientific evidence clearly establishes that my aerobic or ‘cardio’ training doesn't make you fat. And that my friend is how the cardio cookie crumbles!
References
Ahlskog JE, Geda YE, Graff-Radford NR, Petersen RC (2011) Physical exercise as a preventive or disease-modifying treatment of dementia and brain aging. Mayo Clinic Proceedings 86:876–84.
Borsheim E, Bahr R (2003) Effect of exercise intensity, duration and mode on post-exercise oxygen consumption. Sports Med 33:1037–1060.
Brooks G, Fahey, Baldwin (2005) Exercise Physiology: Human Bioenergestics and Its Application.
Burgomaster KA, Howarth KR, Phillips SM, Rakobowchuk M, Macdonald MJ, McGee SL, Gibala MJ (2008) Similar metabolic adaptations during exercise after low volume sprint interval and traditional endurance training in humans. J Physiol 586:151–60.
Coburn J, Mahlek MH (2012) National Strength and Conditioning Association (NSCA) Essentials of Personal Training. 2nd ed. Human Kinetics: Champaign, IL.
Coffey VG, Pilegaard H, Garnham AP, O'Brien BJ, Hawley JA (2009) Consecutive bouts of diverse contractile activity alter acute responses in human skeletal muscle. J Appl Physiol (1985) 106:1187–97.
Collins MA, Snow TK (1993) Are adaptations to combined endurance and strength training affected by the sequence of training? J Sports Sci 11:485–91.
Donnelly JE, Honas JJ, Smith BK, Mayo MS, Gibson CA, Sullivan DK, Lee J, Herrmann SD, Lambourne K, Washburn RA (2013) Aerobic exercise alone results in clinically significant weight loss for men and women: Midwest exercise trial 2. Obesity 21:E219–28.
Dudley GA, Djamil R (1985) Incompatibility of endurance- and strength-training modes of exercise. J Appl Physiol (1985) 59:1446–51.
Falcone PH, Tai CY, Carson LR, Joy JM, Mosman MM, McCann TR, Crona KP, Kim MP, Moon JR (2015) Caloric expenditure of aerobic, resistance, or combined high-intensity interval training using a hydraulic resistance system in healthy men. J Strength Cond Res 29:779–85.
Giannaki CD, Aphamis G, Sakkis P, Hadjicharalambous M (2015) Eight weeks of a combination of high intensity interval training and conventional training reduce visceral adiposity and improve physical fitness: A group-based intervention. J Sports Med Phys Fitness.
Gibala M (2009) Molecular responses to high-intensity interval exercise. Appl Physiol Nutr Metab 34:428–32.
Hakkinen K, Alen M, Kraemer WJ, Gorostiaga E, Izquierdo M, Rusko H, Mikkola J, Hakkinen A, Valkeinen H, Kaarakainen E, Romu S, Erola V, Ahtiainen J, Paavolainen L (2003) Neuromuscular adaptations during concurrent strength and endurance training versus strength training. Eur J Appl Physiol 89:42–52.
Helgerud J, Hoydal K, Wang E, Karlsen T, Berg P, Bjerkaas M, Simonsen T, Helgesen C, Hjorth N, Bach R, Hoff J (2007) Aerobic high-intensity intervals improve VO2max more than moderate training. Med Sci Sports Exerc 39:665–71.
Hickson RC (1980) Interference of strength development by simultaneously training for strength and endurance. Eur J Appl Physiol Occup Physiol 45:255–63.
Jones TW, Howatson G, Russell M, French DN (2013) Performance and Neuromuscular Adaptations Following Differing Ratios of Concurrent Strength and Endurance Training. J Strength Cond Res.
Joyner MJ, Coyle EF (2008) Endurance exercise performance: The physiology of champions. J Physiol 586:35–44.
Kraemer WJ, Fleck SJ, Deschenes MR (2012) Exercise Physiology: Integrating Theory and Application. Wolters Kluwer/Lippincott Williams & Wilkins: Philadelphia.
LaForgia J, Withers RT, Gore CJ (2006) Effects of exercise intensity and duration on the excess post-exercise oxygen consumption. J Sports Sci 24:1247–64.
Lee DC, Artero EG, Sui X, Blair SN (2010) Mortality trends in the general population: the importance of cardiorespiratory fitness. J Psychopharmacol 24:27–35.
Lloyd-Jones DM, Hong Y, Labarthe D, Mozaffarian D, Appel LJ, Van Horn L, Greenlund K, Daniels S, Nichol G, Tomaselli GF, Arnett DK, Fonarow GC, Ho PM, Lauer MS, Masoudi FA, Robertson RM, Roger V, Schwamm LH, Sorlie P, Yancy CW, Rosamond WD, American Heart Association Strategic Planning Task F, Statistics C (2010) Defining and setting national goals for cardiovascular health promotion and disease reduction: the American Heart Association's strategic Impact Goal through 2020 and beyond. Circulation 121:586–613.
MacNeil LG, Glover E, Bergstra TG, Safdar A, Tarnopolsky MA (2014) The order of exercise during concurrent training for rehabilitation does not alter acute genetic expression, mitochondrial enzyme activity or improvements in muscle function. PLoS One 9:e109189.
Macpherson TW, Weston M (2015) The effect of low-volume sprint interval training on the development and subsequent maintenance of aerobic fitness in soccer players. Int J Sports Physiol Perform 10:332–38.
McCarthy JP, Agre JC, Graf BK, Pozniak MA, Vailas AC (1995) Compatibility of adaptive responses with combining strength and endurance training. Med Sci Sports Exerc 27:429–436.
McGawley K, Andersson PI (2013) The order of concurrent training does not affect soccer-related performance adaptations. Int J Sports Med 34:983–90.
Naimo MA, de Souza EO, Wilson JM, Carpenter AL, Gilchrist P, Lowery RP, Averbuch B, White TM,Joy J (2015) High-intensity interval training has positive effects on performance in ice hockey players. Int J Sports Med 36:61–6.
Paoli A, Marcolin G, Zonin F, Neri M, Sivieri A, Pacelli QF (2011) Exercising fasting or fed to enhance fat loss? Influence of food intake on respiratory ratio and excess postexercise oxygen consumption after a bout of endurance training. Int J Sport Nutr Exerc Metab 21:48–54.
Pavlik G, Major Z, Csajagi E, Jeserich M, Kneffel Z (2013) The athlete's heart. Part II: influencing factors on the athlete's heart: types of sports and age (review). Acta Physiol Hung 100:1–27.
Pavlik G, Major Z, Varga-Pinter B, Jeserich M, Kneffel Z (2010). The athlete's heart Part I (Review). Acta Physiol Hung 97:337–53.
Regaieg S, Charfi N, Kamoun M, Ghroubi S, Rebai H, Elleuch H, Feki MM, Abid M (2013) The effects of an exercise training program on body composition and aerobic capacity parameters in Tunisian obese children. Indian J Endocrinol Metab 17:1040–45.
Sale DG, MacDougall JD, Jacobs I, Garner S (1990) Interaction between concurrent strength and endurance training. J Appl Physiol (1985) 68:260–70.
Schoenfeld BJ, Aragon AA, Wilborn CD, Krieger JW, Sonmez GT (2014) Body composition changes associated with fasted versus non-fasted aerobic exercise. J Int Soc Sports Nutr 11:54.
Scott CB (2011) Quantifying the immediate recovery energy expenditure of resistance training. J Strength Cond Res 25:1159–63.
Tabata I, Nishimura K, Kouzaki M, Hirai Y, Ogita F, Miyachi M, Yamamoto K (1996) Effects of moderate-intensity endurance and high-intensity intermittent training on anaerobic capacity and VO2max. Med Sci Sports Exerc 28:1327–30.
Walter B (2011) Medical Physiology. 2nd Edition. Updated. Saunders.
Wang CY, Haskell WL, Farrell SW, Lamonte MJ, Blair SN, Curtin LR, Hughes JP, Burt VL (2010) Cardiorespiratory fitness levels among US adults 20-49 years of age: findings from the 1999-2004 National Health and Nutrition Examination Survey. American Journal of Epidemiology 171:426–35.
Williams LD, Morton AR (1986) Changes in selected cardiorespiratory responses to exercise and in body composition following a 12-week aerobic dance program. J Sports Sci 4:189–99.
Wilson JM, Marin PJ, Rhea MR, Wilson SM, Loenneke JP, Anderson JC (2012) Concurrent training: a meta-analysis examining interference of aerobic and resistance exercises. J Strength Cond Res 26:2293–307.
Wisloff U, Ellingsen O, Kemi OJ (2009) High-intensity interval training to maximize cardiac benefits of exercise training? Exerc Sport Sci Rev 37:139–46.
I wanted to provide everyone with some actual knowledge about me because a large cohort of you mistakenly blame me for aspects of your training that are, frankly, not my fault but perhaps the fault of your own uneducated self. The information presented in this article isn't an intentional jab at any given person or groups of individuals but merely serves as an educational yet informative piece about the history of me. Because I don’t have a last name, just call me Cardio.
I agree. I'm found in nearly every single small and large big box gym in the country as well as in semi-private facilities and strength and conditioning facilities. I usually sit on my ass until a client or athlete decides to use me, and aside from that, I take up too much space because there are way too many versions of me that most people either grossly overuse or don’t know the correct context of how I can actually help them. Although a broad definition, I'm more commonly used to describe the cardiovascular system (also referred to as the circulatory system), which comprises the heart and blood vessels that carry nutrients and oxygen to the body's tissues and eliminates carbon dioxide and other waste materials (3, 5, 18). In fact, my history dates back to the second century AD in Rome. The Greek physician Galen observed that blood vessels carried blood and identified venous (dark red) and arterial (brighter and thinner) blood, each with distinct and separate functions, and William H*****, in the early 1600s, initially pioneered our current conceptualization and current understanding of heart beats and blood flow (35).
How Do I Work
The scientific effects of my impact have consistently focused on health benefits such as with the prevention of diseases including coronary heart disease, type 2 diabetes, hypertension, some cancers and other chronic diseases (20, 21, 36). Other aspects of my research have examined my effect with exercise in reducing stress, depression and anxiety (1). When I’m activated, my cardiovascular effects of exercise performance are centered on heart rate, stroke volume (the amount of blood pumped per beat) and heart contractility (forcefulness of each heart contraction). Collectively, these variables increase blood flow and oxygen supply to meet the demands of exercise training. The contraction of the skeletal muscle also increases venous blood flow return to the heart, which increases ventricle blood filling (called preload and not the stimulant kind in case you’re wondering). This boosted preload contributes to my heart's increased stroke volume during exercise, which is a major determinant of aerobic performance (17).
Brain circulatory system
A wide variety of my structural adaptations are common with progressively increasing amounts of doing my type of training. These adaptations include thickening of the heart muscle and increased left ventricle size, contributing to improved heart function during exercise. Additional adaptations that I provide (17, 28, 29) include the following:
Increased cardiac muscle mass
Increased stroke volume
Disposal of metabolic wastes
Increased oxidative enzymes
Faster diffusion rates of oxygen and fuel into muscle
Increased left ventricle and chamber volume
Increased carbohydrate sparing (thus greater use for fat as fuel)
Increased number of mitochondria
Enhanced fat oxidation (HIIT as well)
Increased expression of fatigue resistant slow twitch muscle fibers
It’s helpful to know that I come in many different shapes and sizes. Specifically, there are numerous training modes to choose from (you know cardiovascular and aerobic fitness), and they all have different outcomes. Considering the overwhelming majority think and believe that I’m a one size fits all approach, allow me to retort some examples:
Type 1, High Intensity Aerobic Interval Training: High intensity aerobic interval training, referred to as a HIT or HIIT programs, are executed by many coaches and trainers. These workouts are described as a compromise between sustained, moderate intensity training and sprint interval training. From the science, I show that the cardiovascular adaptations to HIIT are similar to, and in some cases superior to, those of continuous endurance training (10, 11, 14, 26, 39). Increased mitochondria size and number is something my system now provides you. This has become a hallmark adaptation to HIIT (12). Bet you didn’t know that, huh?
Type 2, Sprint Interval Training: If you aren't performing my sprints via Prowler work, hill sprints or something that directly relates to me in this area, you don’t deserve any cardiovascular adaptations and gains. I'm an all-out cardiovascular effort lasting several seconds to less than two minutes. Research demonstrates that short duration SIT training produces similar cellular fat metabolism adaptations comparable to traditional endurance programs (4).
Type 3, Tabata Style Intervals: Tabata and I go way back. Tabata-style training can use any number of my cardiovascular equipment such as the treadmill, rowing machine or stationary bike or in calisthenics such as burpees, mountain climbers or body weight squats (or even with dumbbells or kettlebells). Tabata is the use of, for example, 20 seconds of high intensity work followed by 10 seconds of rest repeated up to eight times. During the rest interval (i.e. three minutes), the exerciser (you) continues to move to avoid blood pooling in the lower extremities. These training sessions usually last around 25 minutes and have been shown to be effective at improving VO2 max (23, 26, 34, 39).
Type 4, Metabolic Resistance Training: A very popular and highly effective method of me is metabolic resistance training (MRT). This refers to exercise training sessions designed to maximize caloric expenditure and increase the metabolic rate. The main stimulus for metabolic resistance training is to use movement-based exercises or exercise that incorporates larger muscle mass. A benefit of this type of me is do more work in less time or increase exercise density. Specifically, you want to do high reps (i.e. 15) that elicit greater volumes of energy than the higher intensity lifts (over 85 percent) and limit the rest intervals to 30–40 seconds or less per set, which yields a better training density and more work in less time. Surprisingly, little science has been done on me with this training, and although many methods and variations work, evidence-based science guidelines are still lacking, which make me a little sad, but I’m optimistic.
2015-06-26 18.54.20
Why Do Peeps Hate Me So Much?
This is the million-dollar question that everybody wants to know. Over the last few years, coaches, trainers and numerous bodybuilding and fitness competitors have become very outspoken regarding the effects I produce throughout various types of training. Specifically, if you do me (pun intended), I will somehow make you fat. While some information is entertaining and laughable, the majority of it is misleading and an eager attempt to create either online celebrity fitness status or simply a paucity of proper education that perpetuates additional uninformed trainees. Perhaps these are the same people who believe that all calories are created equal and that Anna Nicole married for love!
Why have I been so outlawed by so many in the industry? When did performing my type of sessions suddenly become “badmouthed ” and create the “cardio haters” private only club? Do you know how many scientific studies have been completed for my type of training? It’s thousands! Yes, I said thousands! What about performing my cardio training on measuring body fat? If you cross reference on PubMed ‘aerobic’ with ‘body composition,’ you will clearly be shown over 500 publications and that barely touches resistance training. Further, which version of “cardio" are you incorporating?
Let’s a take a minute to go back in time to the learning tree, shall we? Most people, including average gym goers and even those in competitive strength sports, view “me” as something for endurance and marathon and cycling aficionados who are less physically impressive and have little muscle mass. While this is true for many, let’s start with some actual scientific facts about me.
Going back to the 1980s, 12 weeks of doing some of my wonderful aerobic dance training (three days per week for 45 minutes) resulted in significant increases in lean body mass and body density coupled with decreases in the percentage of body fat and the sum of four skin-fold thicknesses (37). Recently, researchers put 28 obese children (16 boys and 12 girls, aged 12–14 years) into an exercise group or control group. Once again, the exercise group participated in 16 weeks of my aerobic exercise program (ya know, the one you hate) for four, 60-minute sessions per week at 70–85 percent of heart rate max) in addition to the school’s own physical education. Those kids who completed my aerobic exercise not only yielded a smaller waistline, but they also showed a significant drop in fat mass (30).
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Another recent study determined the effect of cardiovascular exercise (oops, I said it again) without energy restriction on weight loss in sedentary, overweight and obese men and women. Subjects were randomized into a 400 calorie/session group, a 600 calorie/session group or a non-exercise control group. Exercise was supervised for five days/week for 10 months. Isn’t it awesome to have science that can dispel witchcraft? Guess what they found? They found that “significant changes in percent body fat over 10 months were observed in both the 400 (- 2.9 percent) and 600 (-4.4 percent) kcal/session groups. Percent fat was unchanged in the control group (-0.6 percent), but the reductions in body weight observed in both exercise groups were a result of decreased fat mass and preservation or increase in fat-free mass.” (8).
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I can’t believe it. Holy crap I actually worked! The group that performed my type of exercise actually lost body weight and fat? Say it isn’t so? Here is the hardcore truth about me—if performing me truly made you fat, why are endurance athletes consistently lean? Some of you will throw the genetics card in my face, but so what? There is a reason this phenomenon occurs. I’ll let you marinate on that for a while. What about volleyball players? They perform me and boxers, too, and a multitude of other sports. Haters gonna hate!
What Are My Effects on Muscle?
It has been known for quite some time that performing too much of me may promote a loss of lean body mass, especially for those wanting more muscle mass. But listen people, that’s not the same as saying ‘cardio makes you fat.’ Oftentimes, this is referred to as “concurrent training or the “interference phenomenon.”
The question often asked is whether performing my particular type of exercise prior to strength training or after will compromise your strength training performance? In other words, will I compromise your gains, bro?
Early research completed on me showed that concurrent training demonstrated that strength improvements are impaired prior to performing my cardiovascular exercise (9, 15) while other studies during this time on concurrent training showed no impairments (24, 31). Interestingly, some science performed on my concurrent training may actually increase muscle mass gain (13, 38). Further (don’t you love science?), the anabolic response to resistance exercise was decreased when preceded by endurance training. Meaning, doing my cardio after trying to get swole patrol increased protein degradation (6) while a recent study showed no significance (22). Lastly (I’m not finished yet), if you discuss the actual training adaptations, research conducted on me (cardio) have shown that doing me (pun intended again) first or last is essentially insignificant (7, 22, 25). If I keep going with this and as you may have guessed, the interference with strength and muscle size gains tend to be reduced if cardio sessions aren't too frequent or of excessive duration (16, 38).
Although a different topic entirely, the key with doing me (yes, I said it again) is to figure out how to do the least amount of volume of me possible to improve performance while also attaining the necessary result. Let’s be clear, this is not an anti-cardio segment on CNN. There are numerous athletes or so called “hybrid athletes” who engage in different athletic disciplines and don't obviously support one type of training or another, such as those competing in powerlifting and endurance competitions. Such athleticism should serve as a good model for those who think that performing me (cardio) will make you small, weak, glycogen depleted and, well, fat (so they say). Sure, performing too much of me (aerobic training) may decrease muscle mass, but it isn't a universal prospect just in case you might go there!
However, I might as well mention dieting. Here’s the main caveat. If you use me for dieting for a physique show, it’s best to continue to adapt to the strength training. If you use me excessively, you will likely have to further decrease your energy output, which results in expending fewer calories for a given movement or training session and results in me using up your most lean tissue (muscle mass) to feed myself. Over time, you will likely over diet, continue to lose your muscle mass (because I took over your life) and your performance and overall physique won't be happy.
shrongher prowler
How Do I Impact Resistance Training and Performance?
This is probably the most misunderstood concept and application that you peeps don’t get about me. Mitochondrial respiration, or the aerobic system (also known as cardio), operates continuously and is probably the most important, both at rest and during training. It is fueled primarily on fat and glucose. It’s the only one that directly requires oxygen to function. Now, despite the fact that this energy system is ongoing, generally speaking, it’s the last system to kick in. However, in highly trained athletes, particularly endurance athletes, my system is so dominate that I actually activate much sooner compared to normal individuals, and I'm able to reach steady state much quicker compared to less trained individuals. The majority of long distance events and sports (marathon, cycling) require exceptional aerobic capacity, as do athletes in all continuous action field and team sports (i.e. soccer, basketball).
Traditionally, the belief was that the best way to develop my oxidative system was through long, slow cardio (you know, the one that people say makes you fat). Times have changed, and although many still do believe this and even though my aerobic system certainly responds well to that type of training, recent research suggests that the oxidative system also works extremely hard to help you recover after high intensity anaerobic efforts (33).
What about you meatheads? Yes I mean you, too! Due to heavy strength training’s intermittent nature, the energy expenditure contributions of weight training are almost always in a non-steady state compared to my type of aerobic exercise that is usually defined as being steady state. What does this mean? Well, a resistance training session corresponds to a series of intermittent/non-steady state waves of intensity and effort for the oxidative system (mitochondrial respiration). Many times, individuals feel “gassed” after high intensity bouts of strength training or conditioning, even though these specific bouts themselves are technically anaerobic (my alter ego). What is happening is that mitochondrial respiration (my oxidative system) moves into hyper-drive in order to replenish the depleted ATP stores and remove the buildup of metabolic byproducts that were produced from the other energy systems (phosphagen and glycolysis).
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Upon cessation of intense lifting or interval work, mitochondrial respiration (yes, me again) continues activity for a few days. This is where the concept and application of excess post-exercise oxygen consumption (EPOC) comes in. This occurrence can burn additional fat and calories up to 72 hours post-training when intensity and duration (especially intensity) are the presiding factors (2, 19).
Here’s the deal—unless you compete in endurance events, performing lots of long, slow cardio is not the best way to train me and enhance my system. You are better off engaging in higher intensity training as a more effective and efficient means to develop my oxidative system and drive fat burning. Lastly, because low intensity aerobic activity enhances recovery from other forms of training, perhaps the best use of oxidative training is as a recovery tool used on non-training days.
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Can You Do Me Fed or Fasted?
Traditionally, the hypothesis and rationale for doing me fasted was based on research showing that low glycogen levels cause your body to shift fuel utilization away from carbohydrates, therefore allowing greater mobilization of stored fat for energy. However, this whole debate (which still occurs) was based on short-term data. No study had actually investigated the effects of my fasted cardio on body fat when subjects were in an energy deficit in efforts to result in weight loss.
A very recent study examined the effects on doing me fed or fasted (32). Twenty young, non-obese (BMI < 30) subjects were recruited to participate in the study. Prior to the intervention, subjects were tested for body composition using a Bod Pod and then pair matched based on initial body mass measurements. Subjects were randomly assigned to one of two groups: my fasted training (FASTED) group that performed exercise after an overnight fast (n =10) or my non-fasted training (FED) group that consumed a meal prior to exercise (n =10). These meals were provided in the form of a shake, which contained 250 calories consisting of 40 g carbohydrate, 20 g protein and 0.5 g fat. Training consisted of three days a week for one hour on a treadmill. Subjects performed a five-minute warm up followed by 50 minutes of walking/jogging at 70 percent max heart rate followed by a five-minute cool down session. Subjects were provided with customized meal plans intended to result in about a 500 calorie deficit. Protein was kept high to maintain lean body mass, and subjects recorded their food via My Fitness Pal on a daily basis so that dietary intake could be monitored. Further, ongoing nutritional counseling was provided to subjects throughout the study to ensure adherence.
After four weeks, the results showed that both groups lost a statistically significant amount of weight (1.6 kg versus 1.0 kg in my FASTED versus my FED groups) and fat mass (1.1 kg versus 0.7 kg in my FASTED versus my FED groups). However, no significant differences were noted between groups in any of the body composition outcomes.
It is often considered that the true benefit of fasted cardio is specific to very lean individuals, including those genetically lean and pre-contest physique and bodybuilders. However, based on this study, there wasn't any evidence that the fasting condition conferred any benefits. However, a similar investigation showed that fat utilization over 24 hours was actually greater when eating prior to performing my fed cardio versus my fasted cardio (27). Therefore, which is better—fed or fasted? Well, my advice is to concentrate on total energy consumption and expenditure and macronutrient ratios that work for you. Whether you perform my type of cardio fasted or fed is a matter of personal preference.
What Can You Do?
As previously discussed, this was mainly written as an informative piece to educate the reader about what I actually do, with actual scientific evidence and not your average “broscience." It is in these efforts that I hope I provided you with a better understanding of my system and the diversity to which I represent. Do as you wish. If you enjoy doing me, do me. If not, don’t. Based on my applications—and there are some exceptions—the overwhelming scientific evidence clearly establishes that my aerobic or ‘cardio’ training doesn't make you fat. And that my friend is how the cardio cookie crumbles!
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