This study was undertaken to look into the effects of intensive exercise on sustained energy expenditure during the day, even at rest. Results from the study showed that after exercising vigorously for 45 minutes, the effects were maintained over the next 14 hours. In fact, on a rest day, a person lost 190 calories less than on a day started with a 45-minute intensive exercise routine. The authors conclude, “The magnitude and duration of increased energy expenditure following a 45-minute bout of vigorous exercise may have implications for weight loss and management.”
There is controversy regarding the amount of time during which energy is spent after a session of intensive physical exercise because there have been no studies to measure the energy spent over the course of an entire day. The metabolic rate following exercise has not been accurately measured in a 24-hour period after exercise. This study attempted to look at the metabolic rate and its changes after a 45-minute session of exercise. The participants were controlled in laboratory-like situations to assess the exact amount of energy that is lost at rest, after exercise for a specified period of time.
* Participants in this study were 10 male volunteers who were healthy and aged between 22 and 33 years.
* The volunteers were asked to stay inside a closed “metabolic chamber” for a period of 24 hours at a time. The study period was split into alternate rest days and exercise days.
* On rest days, the participants had to stay sitting for most of the day, except for performing daily tasks like brushing their teeth, using the bathroom, hand washing, etc. They were served food inside the chamber.
* On exercise days, the volunteers underwent 45 minutes of vigorous cycling in the late morning. They were advised not to perform any other exercise in between testing and were also given food charts to follow. During the exercise session, the amount of oxygen consumed and energy expended was recorded.
* It was noted that on exercise days, participants consumed an average of 659 calories/day more than on rest days. Total energy spent on exercise days was also on an average 750 calories/day more, compared to rest days.
* The difference between energy intake and expenditure was 38 calories/day on rest days and 129 calories/day on exercise days. On both days, intake of energy was less than the use of energy.
* Exercise days showed increased energy use by 190 calories that lasted over 14 hours, compared to rest days.
The authors agree that earlier studies have failed to examine the effects of vigorous exercise by controlling all activities of the participants. This would involve a total restriction on all activities. Also, the intensive exercise is not standardized in studies and varies from 45 to 60 minutes. This study may have future implications in weight management and weight loss programs.
This study found that on a day that included a bout of vigorous exercise, healthy young men lost up to 190 calories extra over the next 14 hours, compared to non-exercise days. This could mean that a short spell of exercise has prolonged effects during the day. It was also noted that participants consumed more and spent more energy on the days of exercise. The study authors affirm that over a 24-hour period, the total energy expenditure difference between rest days and exercise days is almost 750 cal, which can be significant when considering up to three vigorous exercise sessions per week, along with a controlled intake of energy. Thus, the study revealed that vigorous exercise creates a positive energy balance that may allow for better weight loss and weight regulation plans.
For More Information:
A 45-Minute Vigorous Exercise Session Increases Metabolic Rate for 14 Hours
Publication Journal: Medicine & Science in Sports & Exercise, January 2011
By Amy M. Knab; R. Andrew Shanely; Human Performance Laboratory, Appalachian State University, North Carolina Research Campus, Kannapolis, North Carolina