Abstract and Introduction
Purpose: The purpose of this study was to determine the effectiveness of brief intense interval training as exercise intervention for promoting health and to evaluate potential benefits about common interventions, that is, prolonged exercise and strength training.
Methods: Thirty-six untrained men were divided into groups that completed 12 wk of intense interval running (INT; total training time 40 min·wk−1), prolonged running (~150 min·wk−1), and strength training (~150 min·wk−1) or continued their habitual lifestyle without participation in physical training.
Results: The improvement in cardiorespiratory fitness was superior in the INT (14% ± 2% increase in V̇O2max) compared with the other two exercise interventions (7% ± 2% and 3% ± 2% increases). The blood glucose concentration 2 h after oral ingestion of 75 g of glucose was lowered to a similar extent after training in the INT (from 6.1 ± 0.6 to 5.1 ± 0.4 mM, P < 0.05) and the prolonged running group (from 5.6 ± 1.5 to 4.9 ± 1.1 mM, P < 0.05). In contrast, INT was less efficient than prolonged running for lowering the subjects' resting HR, fat percentage, and reducing the ratio between total and HDL plasma cholesterol. Furthermore, total bone mass and lean body mass remained unchanged in the INT group, whereas both these parameters were increased by the strength-training intervention.
Conclusions: INT for 12 wk is an effective training stimulus for improvement of cardiorespiratory fitness and glucose tolerance, but in relation to the treatment of hyperlipidemia and obesity, it is less effective than prolonged training. Furthermore and in contrast to strength training, 12 wk of INT had no impact on muscle mass or indices of skeletal health.
It is well established that factors such as poor cardiorespiratory fitness, adiposity, impaired glucose tolerance, hypertension, and arteriosclerosis are independent threats to health and that physical inactivity increases the risk for premature death and elevates the incidence of the abovementioned unhealthy conditions, which independently or in combination may be considered risk factors for chronic diseases. Epidemiologic cross-sectional investigations and longitudinal intervention studies have provided experimental evidence for the effectiveness of prolonged aerobic exercise training such as continuous running, brisk walking, or bicycling as interventions that may lower the relative risk for developing several metabolic diseases.[3,5,14,25,26] In accordance, a recent pronouncement from the American College of Sports Medicine concludes that between 150 and 250 min of moderate physical activity per week is sufficient and effective to prevent weight gain, and the Centers for Disease Control and Prevention published national guidelines on physical activity and public health as well as the Committee on Exercise and Cardiac Rehabilitation of the American Heart Association have previously endorsed and supported these recommendations for healthy adults to improve and to maintain health.
However, lack of time is a common reason why many people fail to accomplish the "traditional training programs," and metabolic-related disorders arising secondary to a sedentary lifestyle have become a large and expanding health problem in the modern society. In this relation, it is interesting that short but very intense exercise training may induce similar improvements in cardiorespiratory fitness and skeletal muscle oxidative capacity as prolonged training,[6,11] and a recent study reported that very short duration high-intensity interval training substantially improves insulin action. Accordingly, it has been speculated that short-term high-intensity interval training could be a time-efficient strategy for health promotion. Furthermore, in relation to reducing cardiovascular risk factors, studies by Schjerve et al. and Tjonna et al.[30,31] elegantly demonstrate that high-intensity training has a major advantage compared with "isocaloric" moderate intense training. However, because the total energy turnover during training was matched across the different groups in the studies by Schjerve et al. and Tjonna et al.,[30,31] the overall exercise time was not markedly reduced in the intense compared with the moderate training group. Although the abovementioned studies indicate that intense training has the potential to improve various health parameters, it remains unknown if very intense but short-lasting exercise training can completely substitute for the higher training volume and consequently larger energy expenditure associated with prolonged moderate physical activity.
Many health-promoting exercise programs also include strength training, aiming with the intension to develop strength and to induce muscle hypertrophy. The increased lean body mass may increase the basal energy expenditure and favor the loss of body fat; in addition, it could benefit health by other means. Thus, heavy strength training is not only a stimulus for muscle hypertrophy, this type of training also appears to be a potent stimulus for osteogenesis and increased bone mass, and bone mineral density may increase bone strength, which is of major importance for the prevention of osteoporosis later in life. As an alternative to strength training, exercise with a high-impact load may also provide a significant osteogenic stimulus. High-intensity interval running may be considered as high-impact exercise and could therefore be speculated to have an effect on bone mineral density.[12,27] Furthermore, strength training for 30 min three times per week increased insulin action in skeletal muscle in both normal subjects and patients with type 2 diabetes. This effect may in part relate to increased muscle mass and reduced body fat, but it also involves up-regulation of several key proteins in the insulin signaling cascade. In contrast, strength training has limited impact on cardiorespiratory fitness, and the influences on the metabolic capacity of the skeletal muscles and on the plasma lipoprotein profile seem to be minor importance.
The present study was undertaken to clarify how an intervention with brief but very intense aerobic training conducted as high-intensity interval running would influence specific parameters such as plasma lipid profile, glucose tolerance, fat mass, and blood pressure and compare changes in these physiological variables of with adaptations achieved through traditional training interventions. With the ambition to evaluate the efficiency of different training modes for the prevention or treatment of different types of metabolic and musculoskeletal disorders, 36 untrained subject were therefore divided into a control group (CON), a strength-training group (STR), a high-intensity interval running group (INT), and a group that performed "traditional" moderate-intensity running (MOD).
Med Sci Sports Exerc. 2010;42(10):1951-1958. © 2010 American College of Sports Medicine
Cite this: High-intensity Training versus Traditional Exercise Interventions for Promoting Health - Medscape - Oct 01, 2010.