Why resistance training is key to reducing risk of diabetes

Published on 22 February 2023

In a study of 1,170 midlife women, NUHS researchers found that those with poor muscle strength were at a higher risk of diabetes.

One of the most pressing public health concerns in Singapore is diabetes, with approximately one in three individuals in the country at risk of developing the condition in their lifetime.

This prompted the government to launch the "War on Diabetes" campaign in 2016, aimed at raising awareness and providing resources to prevent and manage the disease. With diabetes projected to affect one million Singaporeans by 2050, it is critical that measures are taken to address this issue.

After all, diabetes not only has serious health consequences, but also places a significant economic burden on individuals and the healthcare system.

While factors such as old age, obesity, smoking, and an unhealthy diet are often associated with diabetes risk, a recent study conducted by researchers from the National University Hospital (NUH) and the Yong Loo Lin School of Medicine, National University of Singapore (NUS Medicine), have found that weak muscle strength is linked to prevalence of diabetes among midlife women.

The study – which was conducted last year with 1,170 Chinese, Malay, and Indian women participants between the ages of 45 and 69 – found that midlife women with poor muscle strength were more than two times at risk of developing diabetes compared to those with normal muscle strength. This association was independent of the other known risk factors for diabetes.

One of the study’s lead, Prof Emeritus Consultant, Department of Obstetrics and Gynaecology, NUH, elaborated, “Our study supports the growing recognition of the important role of muscle strength on diabetes. Remarkably, this effect of muscle strength on diabetes is independent of body fat.

“We propose a composite muscle strength index combining both upper and lower body muscle strength to better assess the risk of diabetes.”

The study assessed the participants’ upper body muscle strength by testing their handgrip strength with a device called a hydraulic dynamometer. They also measured their lower limb strength by having participants stand up from a chair five times without using their ams or hands for support.

Participants whose handgrip strength were found to be less than 18 kilograms were deemed to have low upper body strength, while those who took longer than 12 seconds to complete the chair test were considered to have poor lower body strength.

The study found that low upper body strength increased the risk of diabetes by 66%, while poor lower body strength increased the risk of diabetes by 59%. More alarmingly, the risk of diabetes increases to 137% when a person has both poor upper body and lower body strength.

As such, Dr Susan Logan, Senior Consultant, Division of Reproductive Endocrinology & Infertility, Department of Obstetrics and Gynaecology, NUH, who co-led the study with Prof Yong, believes more women in Singapore should include resistance exercises in their daily regime to increase muscle strength.

“A lot of women in employment sit for long hours at work and are sedentary during those hours,” said Dr Logan. “So, all the weight goes around the tummy, and there’s weight gain. They then try to diet or exercise, but for many midlife women, when they want to do the latter, they only think of aerobic workouts like jogging or brisk walking.

“They are not open to resistance training, and they won’t try to build muscles. But resistance training is not about losing weight…it helps with metabolism, and crucially, reduces the risk of diabetes."

Prof Yong added that muscles - which are one of the largest organs in the body - burn sugar as they are metabolically active. “So, the more muscles you have, the faster glucose gets burned,” he explained.

According to Dr Logan, women should aim to do resistance training at least twice or thrice a week, for 20 to 30 minutes each time.

The researchers, however, highlighted that further studies are being performed on midlife women in Singapore to better understand the cause-and-effect relationship between muscle strength and diabetes.

In consultation with Prof Yong Eu Leong, Emeritus Consultant, Department of Obstetrics and Gynaecology, NUH, Professor, Department of Obstetrics and Gynaecology, NUS Medicine, and Dr Susan Logan, Senior Consultant, Division of Reproductive Endocrinology & Infertility, Department of Obstetrics and Gynaecology, NUH, Senior Consultant, Department of Obstetrics and Gynaecology, Alexandra Hospital.