“Thermogenesis” is the term for the process of heat production in warm-blooded animals. Although we expend energy- and burn calories- simply by eating (and digesting food), breathing, and maintaining our normal activities of life– physical activity has by far the most impact on the amount of energy we expend each day. We can expend as much as ten times our resting energy expenditures during continuous “big muscle” activities such as running and walking!
By preceding almost any cardiovascular or strength workout with a suitable period of hyperthermic exposure (i.e., 15 to 60 minutes), the energy expenditure of the workout can be tripled as shown in the study referenced below (1). The 1990 study explored the effect of exercise and thermal stress on energy expenditure in obese and lean subjects. The group of obese subjects comprised 20 women with body weight 81-159 kg. A control group included 12 lean women weighing 51-58 kg. Energy expenditure was assessed by the method of indirect calorimetry with a Spirolyt II apparatus. Heart rate, systolic blood pressure and diastolic blood pressure were measured. The tested subjects were subjected to a 60 W (60 J/s) exercise on a cycle ergometer for 10 minutes. Immediately after the aerobic workout the subjects were exposed to hot air in a chamber at about 60 degrees C. for 30 min. On the following day this sequence was reversed, with exercise following heat exposure. In the obese women the energy expenditure at rest was 93.4 +/- 17.5 W, and during exposure to heat after exercise it was 124.0 +/- 21.3 W. During exercise preceded by heat exposure, the energy expenditure was 436.3 +/- 51.6 W. In lean subjects the corresponding values were lower: 77.5 +/- 6.5 W, 104.0 +/- 14.8 W, 376.8 +/- 36.1 W.
The exposure to physical exercise before thermal stress increased the energy expenditure in relation to that caused by each of these exposures separately (in the obese women the energy expenditure increased from 93.4 W. to 124 W.). The exposure to physical exercise after 30 minutes of thermal stress, however, more than tripled the energy expenditure in relation to that caused by each of these exposures separately from 93.4 W. to 436.3 W.!
1. Katedry i Kliniki Gastroenterologii Sl. AM w Katowicach, Effect of physical exercise and heat on energy expenditure in obesity].Polskie archiwum medycyny wewnȩtrznej (Impact Factor: 2.12). 04/1990; 83(3):120-6. Source: PubMed
Research has established that increased body heat significantly increases calorie burning both DURING hyperthermic sessions and long afterward. Physiology textbooks say that each drop of sweat removes calories and heat from our bodies and causes the lost water to evaporate into the air! When a person loses one liter of sweat it translates into 580 calories being removed from the body.
It is important to understand that the sweat lost due to hyperthermic exercise is NOT just water weight. Some of the immediate weight lost will in fact be water weight, which will be regained upon re-hydrating. But the calories lost and burned as a result of hyperthermic exercise are lost and gone forever due to the thermogenic effect — just as is the case with jogging, walking or cycling.
Studies show that a heat-conditioned person can easily sweat off 500 or more grams (one half liter) during a hyperthermic conditioning session— which represents burning from 300 to 500 calories depending on the person! And 300 – 500 calories is like running from 2 to 3 miles. With more hyperthermic conditioning sessions, a heat-conditioned person can increase sweat output from 600 to 800 calories – the equivalent of running 3 to 6 miles! Furthermore, you will continue burning more calories for up to 24 hours after hyperthermic conditioning sessions due to the “afterburn” effect.
APL (American Performance Labs) is a research group dedicated to the collection, analysis, and dissemination of published research and articles on the science of hyperthermia and the various applications, technologies and protocols for the use of hyperthermic conditioning.