Exercise in cold water may slow weight loss

[Posted: Thu 05/05/2005 - www.irishhealth.com]

If you are planning to join an aqua-aerobics class in an attempt to lose weight, make sure the water is warm. A new study has found  that exercising in cold water may increase a person's appetite, making it harder to shed excess pounds.

The study followed the progress of 11 people as they underwent a rigorous exercise routine in water. The particpants, all aged between 21 and 31, had to ride a stationary bike while submerged in water for 45 minutes. They exercised in cold water (68 degrees Fahrenheit) and warm water (91.4 degrees Fahrenheit). They also rested for 45 minutes.

The study found that all of the participants used a similar amount of energy during the exercise, burning 517 calories in cold water and 505 in warm water. After each exercise session and rest period, they were left to rest for one hour in a room with free access to a standard assortment of food of known calorific values. However they were unaware that their calorie intake was being measured at this point.

"We found that during the recovery period when the subjects had access to an assortment of foods, significantly more calories were eaten after exercise in cold water compared to exercise in warm water or at rest", said researcher Lesley White of the University of Florida.

In fact, calorie intake after exercise in cold water was 44% higher than exercise in warm water and 41% higher than the rest period.

Ms White designed the study in an attempt to determine why people who want to lose weight tend to lose less if they undertake acquatic exercise, compared to, for example, jogging.

"It's possible that individuals who exercise in cooler water may have an exaggerated energy intake following exercise, which may be a reason why why they don't lose as much weight. So it may not be the exercise itself that causes the problem because you can match the exercise energy expenditure; rather it's the increased eating after the exercise is over", said Ms White.

She added that the findings do not suggest that aqua activities are ineffective, but that cold water temperature 'could frustrate weight loss by increasing calorific intake'.

Details of this study are published in the International Journal of Sport Nutrition and Exercise Metabolism.