Exercising in the heat may help you eat less
Exercisers trying to cut down on calories might want to take a run in
the sun instead of a climate-controlled gym, according to a small
Australian study.
The study of 11 physically active men found that participants ate
less immediately after working out in hot conditions - about 97 degrees
Fahrenheit (36 Celsius) - than in a more moderate, 77 degree Fahrenheit
(25 degrees Celsius) environment.
Outdoor Exercising |
On average, the men ate roughly 300 calories more when they worked
out in moderate temperatures than when they exercised in the heat.
"Our findings suggest that if you exercise in a warmer environment
you will eat less in the subsequent meal," researcher Dr. Kym Guelfi, of
the University of Western Australia's School of Sports Science, told
Reuters Health. In theory, she said, that would be a good strategy for
exercisers trying to lose weight. However, Guelfi added, future studies
should look at whether warm-weather exercisers just make up for the
smaller meals with larger ones later in the day.
For the study, which is published in the American Journal of Clinical
Nutrition, the researchers had 11 young, regularly active men make
several visits to the exercise lab.
During one visit, the men ran on a treadmill for 40 minutes in 97
degree heat; on another visit, they performed the same workout under 77
degree conditions. On a third visit, they rested in a moderately warm
room.
In all three situations, the men were then presented with an
all-you-can-eat breakfast buffet and were found to eat the most after
working out in moderate conditions.
The study also found clues as to why exercising in the heat may dull
appetite. After the hot workout, the men typically showed higher blood
levels of peptide YY, a hormone produced in the digestive tract that
serves a "fullness" signal.
The men's smaller appetites also appeared to be related to the
increases in core body temperature that came with the hot workouts. The
reasons for this are not clear, but Guelfi noted that some researchers
believe that, because eating produces heat in the body, food intake is
one of our natural mechanisms for controlling body temperature.
"This is why, anecdotally, cold environments have been said to lead
to an increase in appetite," she said. But while a warmer environment
may help curb post-exercise appetites, Guelfi cautioned against taking
that idea to extremes.
"Exercise should not be performed in overly hot environments due to
the risk of dehydration and heat illness," she said.
Reuters |