A small new study has explored the effect of heated exercise on eating.

We all know that a six pack starts with what we put on our plates. But exercise can impact what we are likely to put on our plate.

It is well known that many of us exercise to lose or maintain our weight, yet exercise generally increases our appetite.

There is also a tendency to compensate for our exertion and reward ourselves by consuming more calories. This has been one explanation for why some people put on weight (fat, not muscle) when they begin exercising.

Now, the new study, by the University of Aberdeen in Scotland has found that the temperature during exercise also affects our appetite and how we are likely to eat once we've worked out.

The researchers knew that swimmers tend to eat more after exercise compared with those who complete a similar amount of exercise on land.

To test whether it was the cold of the water rather than the efforts exerted while swimming, they recruited 16 sedentary adults and put them through their paces on a treadmill.

After exercising in both cold (8 degrees Celsius) and warm (20 degrees Celsius) conditions, the participants were offered an all you can eat buffet.

Measures of metabolic rate, endurance capacity and appetite hormones (like the satiating ghrelin) were taken before and after the exercise as well as after the meal.

Interestingly, the participants burned no more calories while exercising in the cold (contrary to the belief that the body has to work harder in cold conditions).

In fact, the researchers found that working out in the warmer conditions burned more calories as, they hypothesised, the body had to work harder in order to keep itself cool.

Additionally, the researchers found that, after exercising in the cold, participants felt far hungrier, piled more on their plates and consumed more carbohydrates.

Associate Professor Corinne Caillaud, from the faculty of Exercise and Sport Science at the University of Sydney says other research supports the finding that those who exercise in heat tend to eat less afterwards.

She also says that upcoming research will further explore the impact exercising in heat has on the metabolism.

There are, for instance, heat shock proteins in the body which are stimulated by heat. Future research, Caillaud says, will target the expression of these specific proteins for glucose control and weight management.

Indeed.

One 2010 study turned up the heat on exercise and compared the different ways we burn fuel in 40 degree Celsius heat versus 20 C.

It was found that exercising at the same intensity in the 40 C heat increased the muscle glycogen oxidation in all participants.

A separate study from 2010 found that exercising in the heat may improve athletic performance.

Results like these help to explain the increasing propagation and popularity of heated exercise classes like balmy Bikram (37 degrees C) yoga and power (30 C) yoga.

"Exercise in the heat can be beneficial," Caillaud says, but points out that exercise in the cold can too.

She explains that hot and cold temperatures target the metabolism differently. Although researchers didn't look at energy intake after exercise, she points to one body of research which is exploring how exposure to cold during exercise might stimulate brown adipose tissue, which helps to warm us up and which burns more energy.

She also reminds us that exercising in heat is challenging in terms of cardiovascular stress, that there is an increased risk of dehydration and that some people's bodies are better able to handle the heat.

"The way we adapt is different depending on the humidity," she explains, noting the difference between exercise in a temperature-controlled room versus going for a run in the heat of the midday summer sun.

"You have to be careful about how you go about it."

The good news is that it seems, whatever the weather, we can use it to our advantage to stimulate our bodies differently and keep them from plateauing.

"It's a very interesting field," Caillaud says. "It's a way to use the environment instead of avoiding it. The body will progressively adapt and the different stimulation will help."