Abstract
The positive effect of high intensity cardio exercise on body fat is well known. The paper looks into the greater impact on body composition due to those high-intensity exercises. Regular cardio is known to increase both aerobic and anaerobic fitness. Until recently, it was thought that low intensity exercises like walking or slow jogging burn more fat and high intensity workouts like running or high intensity aerobics are meant more for cardiovascular fitness and not for burning fat. However, now the evidence from scientific studies and controlled trials is showing that high intensity cardio may actually burn faster and decrease the body fat percentage at an accelerated rate. We conduct a search of the literature and examine the evidence in the scientific literature that looks at high intensity cardio workouts and their impact on your health and fitness. The evidence supporting high intensity workouts is overwhelming and suggests that this is a better strategy for people looking to burn fat as well as those looking to improve their cardiovascular fitness.
Introduction
Too much of body fat can lead to life threatening diseases such as high blood pressure, type 2 diabetes, stroke, heart disease, and certain cancers. Recent research and studies on high-intensity cardio exercises and their role in burning body fat show promising results. The body can carry out normal healthy functioning only when its fat is within acceptable ranges. If the body fat is located around the abdomen, it can increase the risks of the above life-threatening conditions. Truncal obesity has long been established with an increasing risk of adverse cardiovascular events. Therefore, everyone with a beer belly or a tendency to put on weight around their midline have a strong incentive to lose that abdominal fat to improve their overall fitness.
For a long time, the thought was that low intensity exercises like walking or slow jogging are ideal for inducing fat loss. High intensity exercises were thought to be designed more for cardiovascular fitness rather than burning fat cells. Although most of these exercises are designed to induce fat loss, studies have shown that moderate exercises like walking do not lead to any remarkable results. Accumulating evidence suggests that high-intensity cardio is an effective exercise protocol to reduce body fat percentage (Wu et al, 2009). When scientists first stated that intensive exercises can help body burn glycogen that remains stored in the muscles for energy, there was a change in the outlook of exercises. For a long time, everyone had been recommending low intensity workouts to burn fat. Overnight, people starting to change their routine from low intensity exercises to high intensity exercise to burn body fat. The scientists were right when they reported that you will burn more calories during 15 minutes of intensive swim as compared to half an hour of walk. In this paper, we review the evidence and see what the literature has shown when it comes to high intensity cardio and burning fat in general. The results of several high quality scientific papers have been surprising and will likely influence the way people work out at the gym in the future.
Data from earlier studies have indicated a high risk for cardiovascular disease or diabetes for those with higher body fat percentage. WHO proposed normal limits of BMI or Body mass index range from 17.9 to 24.5 kg/m2. A higher body fat % (BF) has been observed within this normal range of BMI. When comparing the body fat percentage, body builder show percentage down as low as 4-8%. Average body fat % ranges from 18-20%, while an overweight person can show more than 30% of body fat. Both BMI and BF are independent predictors of mortality in patients. However, a combined BMI and BF offer particularly higher risks (Lavie et al, 2011). The acceptable range of body fat % is 25-31%.
New research links the body fat percent directly to BMI and thus it helps one to understand health risks. It is not possible to measure the exact body fat in a living person as the different methods require special laboratory equipment. Skinfold measurements are taken from a different location to estimate total body fat. However, the measurements taken over time may vary.
There are complex cardiometabolic issues associated with aging, lack of exercise and body fat percentage. The abdominal visceral fat is especially associated with increased cardiometabolic risks. Researchers and clinicians all across the world are looking for different approaches to lower visceral adiposity and its related issues. The right exercise training offers an economically viable approach for causing positive adaptations in body composition. The high-intensity training has proved to be a powerful strategy for reducing abdominal fat loss as well as lower body fat % (Irving et al, 2008).
Despite work done on the exercises that can help maximize fat loss, the optimal exercise remains elusive. It may be hypothesized that high-intensity cardio can induce greater fat loss, in particular. A study was done in inactive and overweight men who were similar in terms of age to evaluate the impact of high-intensity exercise on Abdominal, Visceral, and Subcutaneous Fat Mass. Subjects in high-intensity intermittent exercise training completed supervised exercise. Data gathered and evaluated showed that the total, abdominal, visceral, and subcutaneous fat was significantly reduced in the high-intensity exercise group. Total body mass as well as the Fat Mass too decreased significantly.
The Effect of High-Intensity Intermittent Exercise
Another study was done to evaluate the effect of intensity of physical activity on body fat and fat distribution. The data from 1981 Canada Fitness Survey was analyzed (Tremblay et al, 1990) and the thickness of subcutaneous skinfold thicknesses was measured for both sexes. Exercise training and its beneficial effects as a weight-reducing strategy are well accepted. Several investigators observe that exercise training can help reduce body fat and weight. Further investigations reveal that the subjects where the quantity of exercise performed was high and intense, there was a substantial weight loss. Thus, it indicates that the high-intensity cardio and exercises do have an impact on the level of energy expenditure. There are numerous health problems associated with being overweight. Following the right diet is important too, but effective fat loss strategies too are required. Aerobic exercise programs are especially known to raise cardiorespiratory fitness and maintain fat-free mass. The moderate-intensity exercise comprises of about 30 to 40 min for 3 to four days per week (Heydari et al, 2012). These kinds of exercise programs do not lead to the desired results of higher fat loss. In contrast, high-intensity intermittent exercise (HIIE) and high-intensity cardio lead to higher fat loss. The study was done on two groups of young women, with one group following low-intensity exercise program like walking for 20 min sessions per week or low-intensity cycling. Another group of women was asked to carry high-intensity aerobic cycling for 40min each session.
Prevalence of obesity continues to present ever-increasing challenges for individuals, as well as health professionals. Overweight individuals are already at risk of diabetes, cardiovascular disease and other health disorders. Where and how the fat is distributed is of particular importance as there is a strong relation between obesity and disease. There is controversy regarding the amount of exercise required for health benefits. There have been exercise training studies on the effects of different intensities of exercise on the parameters of central obesity (Cris et al, 2005). The intensity on cardiovascular risk factors in overweight men and women can be seen in the risks of overweight men and women.
When comparisons were made between the different groups illustrating the effects of continued physical inactivity, as well as intensities of exercise training, it was found that high-amount group lost more visceral fat as compared to the low-dose groups. It is clear from the results that the high-amount exercise group lost a significant amount of subcutaneous abdominal fat. Although overall obesity is known to cause higher risks, the presence of abdominal fat is clearly related to the risk for these diseases. Athletes and individuals looking to increase fat oxidation during exercise place higher importance on increased muscle fatty acid oxidation. Another study shows HIIT over a 2-wk period shows improvement in the whole body fat oxidation and a higher capability for skeletal muscle to oxidize fat (Jason et al, 2007). The intensity of exercise carries the potency to stimulate the skeletal muscle for an improved performance and health. The high-intensity exercise performance increases the body exercise fat oxidation rates.
It is reported that regular aerobic exercises have a negligible effect on body fat. According to emerging research, it is a high-intensity exercise that places a greater impact on body composition. The high-intensity intermittent exercises are known to be more effective at minimizing abdominal body fat as compared to other forms of exercise. However, more research needs to be done in how the fat reduction is induced by high-intensity forms of exercises. Regular high-intensity exercise has shown to increase both aerobic and anaerobic fitness (Boutcher, 2011). The response of heart rate is particularly dependent on the nature of the high-intensity protocol. There is also an indication that the muscle aerobic capacity too increases after the high-intensity cardio. Therefore, high intensity cardio results in skeletal muscle remodeling in a way that impacts the overall fat and calories you burn even when you’re not actively working out. Therefore, 30 minutes of high intensity training can actually improve the overall number of calories you burn during the day and the amount of fat you lose even when you’re just sitting in a chair. In case of some studies, there have been longer programs to evaluate the impact of high-intensity exercise on abdominal fat loss. It has been found that as compared to a steady state exercise group, a high-intensity cardio group lost more subcutaneous fat. Another study using longer duration HIIE protocols for overweight adults and obese with larger initial fat mass showed greater fat reduction. However, the normal weight and slightly overweight males showed modest reductions in weight due to high-intensity exercises. It makes sense that the more fat you have, the more you lose with a high intensity cardio regimen. However, even the modest reductions in the other groups of males have a positive health impact and suggest a significant benefit for this particular exercise regimen.
Studies show acute responses to HIIE and these include hormones, metabolic reactivity, heart rate and hormones. Heart rate is significantly elevated during exercise and even hormones like growth hormones, catecholamines and cortisol (Boutcher, 2011). Catecholamine especially is known to drive lipolysis and is responsible for the release of fat from both subcutaneous and intramuscular layers. Thus, this strongly indicates that high-intensity cardio has a higher potential to lower abdominal fat stores. HIIE seems to have a stronger effect on blood glucose levels of exercising. These exercises improved skeletal muscle adaptations and increased aerobic and anaerobic fitness.
Conclusion Based on the above studies, it is clear that high-intensity cardio exercises have a dramatic effect on the body weight and fat percentage. This is good news for all those looking for more from their workouts. High-intensity cardio offers you a new challenge during your workout, and there is a huge range of exercises to pick from. One not only achieves weight loss, but also other health benefits like keeping your sugar levels under better control and improving cardiovascular health. Most people discuss their weight problems and other health issues before getting into a high HIIT training routine. Everybody is unique with a different body fat and BMI. Body fat is essential to survival as it keeps our internal organs safe. This is known as the “Essential fat”, as it means the least amount of fat required by our body to survive (Anonymous, 2009). It is important to maintain the right body weight percentage to stay healthy and function properly. Like BMI, there is a normal fat percentage and too little fat is just as bad as a too low BMI. The healthy balance is important to achieve optimum fitness. The high intensity cardio exercises can keep your metabolism high even after a workout. This means that the body continues to burn body fat after you have stopped working. These impacts are not seen in the low intensity cardio workout. The literature so far is overwhelming in supporting a high intensity cardio workout as important for maintaining both a healthy BMI and body composition.
References
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