Women's weight gain could be prevented by daily spa activity, study finds

A new study has suggested a daily sauna session could be the key to preventing weight gain in middle-aged women. Researchers using mice have found regular exposure to a warm environment, akin to a sauna, might help older individuals, particularly women, fend off age-related obesity and insulin resistance.

Scientists are touting heat treatments as an uncomplicated method to encourage healthier ageing. The American team discovered older female mice subjected to a 30-minute whole-body heat treatment every day experienced less weight gain and better insulin regulation, which is vital for controlling blood sugar levels.

They also pinpointed the specific biological mechanisms behind these positive outcomes.

"Compared to men, women have a higher likelihood of being obese or overweight," said Professor Soonkyu Chung from the University of Massachusetts, Amherst, who led the research team. "This is especially true after menopause, due to the loss of oestrogen in the body.

"Our study suggests that whole-body heat therapy could serve as an effective, non-invasive solution for managing weight gain and insulin resistance associated with menopause."

Rong Fan, a doctoral student advised by Prof Chung, remarked: "Heat therapy could be a practical option for those with increased abdominal fat and a higher risk of metabolic diseases triggered by menopausal hormonal changes."

"It could be easily integrated into routine healthcare practices through regular sessions in saunas, heated baths or with specialised heat wraps."

The study involved modelling post-menopausal conditions by removing the ovaries of older female mice. To simulate weight gain, the rodents were fed a Western diet high in fat, with 45% of calories coming from fat sources.

A group of these mice was subjected to daily 30-minute sessions of heat therapy in a chamber set at 40 degrees Celsius (104F) for a duration of 12 weeks, while a control group did not receive any form of heat treatment.

The mice that underwent heat therapy showed no signs of tissue damage and had "significantly" lower levels of lactate dehydrogenase, which suggests reduced ageing-related tissue damage.

Additionally, the heat therapy proved effective in curbing weight gain that was induced by the high-fat diet.

In comparison to their untreated counterparts, the mice that received heat therapy exhibited "significant" improvements in insulin sensitivity and signalling, along with a decrease in fat deposits in critical areas such as the liver and brown fat.

The researchers highlighted while white adipose tissue is responsible for storing energy, brown fat is a metabolically active type of fat that aids in burning more energy. It has been previously established individuals tend to lose brown fat with age and during menopause, leading to a slower metabolism.

The research team delved into the molecular mechanisms that underpin the positive effects of heat therapy. The researchers discovered heat triggers several molecular processes that enhance the body's efficiency in energy usage and fat burning.

A protein known as TRPV1, which functions as a calcium ion channel in the cell membrane, plays a significant role. When activated by heat, TRPV1 initiates a process called "futile calcium cycling", where the body utilises energy - in the form of ATP - to pump calcium ions across cell membranes.

According to scientists, this process boosts the amount of energy the body burns.

The activation of TRPV1 and the subsequent calcium cycling also stimulate the breakdown and burning of fats, reducing fat accumulation in tissues such as the liver and improving the body's insulin sensitivity, which is vital for overall metabolic health.

Ms Fan stated: "This series of events suggests that regular application of heat can mimic the effects of calorie burning and fat. It could be particularly advantageous for individuals who find physical activities challenging, providing a relaxing way to improve metabolic health."

The team emphasised more research is needed to determine the optimal duration and intensity of heat exposure in people for health benefits. The findings were presented at the annual meeting of the American Society for Nutrition in Chicago.

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