Title: Ageing of the cardiovascular system during 33 years of aerobic exercise Author(s): F. Kasch; J. Boyer; P. Schmidt; R. Wells; J. Wallace; L. Verity; H. G uy; D. Schneider Source: Age and Ageing Volume: 28 Number: 6 Page: p531 -- p536 Publisher: Oxford University Press Abstract: Background. Increasing age affects aerobic capacity, with an average loss of 10% or more per decade. Aim. To determine the effect of ageing on the circulatory system in middle-aged men during 33 years of physical training. Method. 15 men initially aged 45 years took part in an exercise training programme for 25-33 years. Nine serial measurements were made at rest and during maximal effort. Aerobic training consisted of swimming, jogging, walking and cycling 3-4 times per week. Sessions were for 61-70 min at 77-84% of heart rate reserve. Results. There was no change in resting heart rate, blood pressure, percentage ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ fat or body composition. ^^^^^^^^^^^^^^^^^^^^^^^^^ Conclusion. Exercise training has a favourable effect on ageing of the ......... no rise in resting blood pressure and no change in body composition. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Aerobic exercise has a small effect on the rate of fat loss Some answers come from a recent review of several hundred weight loss studies, c onducted by Dr Wayne Miller and colleagues at The George Washington University M edical Centre (Miller et al.,1997). The team examined 493 studies carried out be tween 1969 and 1994. Miller and his associates wanted to determine whether the addition of aerobic exercise to a restricted calorie diet accelerated weight loss. Twenty-fi ve years of weight loss research showed that diet and aerobic exercise provides only a very marginal benefit (in terms of weight loss) when compared to diet alone. TABLE 1. Average weight loss over a 15-week period Method Weight Loss Aerobic exercise 3.3kg (7.3lb) Restricted calorie diet 7.8kg (17.2lb) Exercise and diet 9kg (19.8lb) This is not the only research to cast doubt over the effectiveness of moderate a erobic exercise. A study completed at Appalachian State University also showed l ittle effect on body composition over a 12-week period (Utter et al 1998). The research team assigned a group of 91 obese women to one of four groups. Grou p one followed a restricted calorie diet (1,200 - 1,300 calories per day), group two performed moderate aerobic exercise for 45 minutes, five days each week, wh ile a third group combined the exercise and diet programme. The fourth group acted as contr ols. TABLE 2. Fat loss following a 12-week programme of diet and exercise Method Weight Loss Aerobic exercise 1.3kg (2.9lb) Restricted calorie diet 6.8kg (15lb) Exercise and diet 7.2kg (15.8lb) "Moderate exercise training," says Alan Utter, the researcher leading the study, "has a minor, nonsignificant effect on fat mass." Despite the popular support for aerobic training, it does not appear to signific antly accelerate fat loss, even when combined with a low calorie diet. When perf ormed without restricting calories, moderate aerobic exercise has only a very sm all effect on body fat levels. Why moderate aerobic exercise is so ineffective This isn't surprising when you consider how many calories are contained in a pou nd of fat. Each pound of fat contains the equivalent of approximately 3,555 calo ries (McArdle et al., 1991). The most fundamental aspect of any fat loss programme is to create a caloric def icit - to expend more calories than are consumed. Unfortunately, moderate aerobi c exercise has only a moderate caloric requirement - around 187 calories per ses sion (Utter et al., 1998). Based on this estimate, it could take up to 19 moderate aerobic workouts to lose just 0.45kg (1lb) of fat. This might come as a surprise to those of you using the calorie counters on exer cise machines to monitor energy expenditure during a workout. Unfortunately, the se digital readouts are not always accurate. The most reliable way to assess ene rgy expendi ture during exercise is to measure oxygen consumption. Each litre of oxygen that you consume generates approximately five calories of energy. For example, if yo u were to exercise for 30 minutes and consume 30 litres of oxygen, you would hav e expended approximately 150 calories (five calories x 30 litres). Without directly measuri ng oxygen consumption, it's difficult to establish an accurate estimate of energ y expenditure during a workout. A second factor affecting the reliability of calorie counters is the difference between net and gross energy expenditure. Gross energy expenditure refers to the energy cost of exercise plus the metabolic rate. Net energy expenditure refers to just the energy cost of exercise. Calorie counters often display gross energy expenditur e - so they don't accurately represent the additional energy that is used during exercise. In fact, during a 45 minute workout, net and gross energy expenditure can differ by almost 30% (Utter et al., 1998). The moral? Don't always believe what the ma chine tells you. Another popular misconception is the idea that aerobic exercise increases calori c expenditure AFTER a bout of exercise, thus making a further contribution to fa t loss. Unfortunately this is not always the case. Excess post-exercise oxygen c onsumption (the name given to the increase in caloric expenditure following a workout) is m ore likely to occur after high intensity exercise. Moderate aerobic exercise has very little effect on post-exercise metabolic rate (Sjodin et al., 1996). Furth ermore, whe n an increase in physical activity results in a caloric deficit (as would occur with diet and exercise), there is evidence to show that the metabolic rate does not rise at all (Sjodin et al., 1996). Does this mean that aerobic exercise is a waste of time? Definitely not. ….. References · Abe, T., Kawakami, Y., Sugita, M., & Fukunaga, T. (1997). Relationship betwe en training frequency and subcutaneous and visceral fat in women. Medicine and S cience in Sports and Exercise, 29, 1549-1553 · Buemann, B., and Tremblay, A. (1996). Effects of exercise training on abdomi nal obesity and related metabolic complications. Sports Medicine, 21, 191-212 · Dishman, R.K. (1991). Increasing and maintaining exercise and physical activ ity. Behaviour Therapy, 22, 345-378 · Johnson, M.F., Nichols, J.F., Sallis, J.F., Calfas, K.J., & Hovell, M.F. (19 98). Interrelationships between physical activity and other health behaviors amo ng University women and men. Preventive Medicine, 27, 536-544 · Leith, L.M. (1992). Behaviour modification and exercise adherence: a literat ure review. Journal of Sport Behaviour, 15, 60-74 · McArdle, W.D., Katch, F.I., Katch, V.I. (1991). Exercise physiology. Energy, nutrition, and human performance (third edition). Lea & Febiger, Philadelphia, USA · McGuire, M.T., Wing, R.R., Klem, M.L., Seagle, H.M., and Hill, J.O. (1998). Long-term maintenance of weight loss: do people who lose weight through various weight loss methods use different behaviors to maintain their weight? Internatio nal Journal of Obesity, 22, 572-577 · Miller, W.C., Koceja, D.M., & Hamilton, E.J. (1997). A meta analysis of the past 25 years of weight loss research using diet, exercise or diet plus exercise intervention. International Journal of Obesity, 21, 941-947 · Sjodin, A.M., Forslund, A.H., Westerterp, K.R., Andersson, A.B., Forslund, J .M., and Hambraeus, L.M. (1996). The influence of physical activity on BMR. Medi cine and Science in Sports and Exercise, 28, 85-91 · Utter, A.C., Nieman, D.C., Shannonhouse, E.M., Butterworth, D.E., & Nieman, C.N. (1998). Influence of diet and/or exercise on body composition and cardiores piratory fitness in obese women. International Journal of Sport Nutrition, 8, 21 3-222 -- ╭╯ ╮ ║ ☆ ╭═╬═══╯ ╠═════ ═╩╗ ║ ║ ╰╮╰══╬══╯ ╭╯══╮ ╯════ ╭╦╯ ║ ☆ ╰═════╣ ║ ╭╯╠══╣ ╮══╭ ╮ ║║║═╬═╯ ╭════╮ ╭═╯═╮ ╠══╣★ ╰══╯ ║ ║║║ ║ ║★ ║ ║ ║ ║ ║ ═╬═ ║ ╰║╰ ║ ╰════╯ ╰╯ ╰╯ ╯ ╯ ══╬══╰ ╰╯ ═╩═╯ --

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