Midlife Health: More Than Waist Size

Words: Prof Robert NEWTON

You’re not in your 20s, or 30s, anymore and you know regular health checks are important. So you go to your GP. During the appointment they measure your waist. They might also check your weight. Looking concerned, they recommend some lifestyle changes.

GPs and health professionals commonly measure waist circumference as a vital sign for health. This is a better indicator than body mass index [BMI] of the amount of intra-abdominal fat. This is the really risky fat around and within the organs that can drive heart disease and metabolic disorders, such as type-2 diabetes.

Men are at greatly increased risk of health issues if their waist circumference is greater than 102 centimetres. Women are considered to be at greater risk with a waist circumference of 88 centimetres, or more. More than two-thirds of Australian adults have waist measurements that put them at an increased risk of disease. An even better indicator is waist circumference divided by height, or waist-to-height ratio.

But we know people [especially women] have a propensity to gain weight around their middle during midlife, which can be very hard to control. Are they doomed to ill-health? It turns out that, although such measurements are important, they are not the whole story when it comes to your risk of disease and death.

How Much Is Too Much?

Having a waist circumference to height ratio larger than 0.5 is associated with greater risk of chronic disease as well as premature death, and this applies in adults of any age. A healthy waist-to-height ratio is between 0.4 to 0.49. A ratio of 0.6, or more, places a person at the highest risk of disease.

Some experts recommend waist circumference be routinely measured in patients during health appointments. This can kick off a discussion about their risk of chronic diseases and how they might address this.

Excessive body fat and the associated health problems manifest more strongly during midlife. A range of social, personal and physiological factors come together to make it more difficult to control waist circumference as we age. Metabolism tends to slow down mainly due to decreasing muscle mass because people do less vigorous physical activity, in particular resistance exercise.

For women, hormone levels begin changing in midlife and this also stimulates increased fat levels, particularly around the abdomen. At the same time, this life phase [often involving job responsibilities, parenting and caring for aging parents], along with elevated stress can lead to increased cortisol, which causes fat gain in the abdominal region.

Midlife can also bring poorer sleep patterns. These contribute to fat gain with disruption to the hormones that control appetite.

Finally, your family history and genetics can make you predisposed to gaining more abdominal fat.

Why The Waist?

This intra-abdominal, or visceral fat, is much more metabolically active [it has a greater impact on body organs and systems] than the fat under the skin [subcutaneous fat].

Visceral fat surrounds and infiltrates major organs such as the liver, pancreas and intestines, releasing a variety of chemicals [hormones, inflammatory signals, and fatty acids]. These affect inflammation, lipid metabolism, cholesterol levels and insulin resistance, contributing to the development of chronic illnesses.

The issue is particularly evident during menopause. In addition to the direct effects of hormone changes, declining levels of oestrogen change brain function, mood and motivation. These psychological alterations can result in reduced physical activity and increased eating — often of comfort foods high in sugar and fat.

But these outcomes are not inevitable. Diet, exercise and managing mental health can limit visceral fat gains in midlife. And, importantly, the waist circumference [and ratio to height] is just one measure of human health. There are so many other aspects of body composition, exercise and diet. These can have much larger influence on a person’s health.

Muscle Matters

The quantity and quality of skeletal muscle [attached to bones to produce movement] a person has makes a big difference to their heart, lung, metabolic, immune, neurological and mental health as well as their physical function.

On current evidence, it is equally, or more, important for health and longevity to have higher muscle mass and better cardiorespiratory [aerobic] fitness than waist circumference within the healthy range.

So, if a person does have an excessive waist circumference, but they are also sedentary and have less muscle mass and aerobic fitness, then the recommendation would be to focus on an appropriate exercise programme. The fitness deficits should be addressed as priority rather than worry about fat loss.

Conversely, a person with low visceral fat levels is not necessarily fit and healthy and may have quite poor aerobic fitness, muscle mass, and strength. The research evidence is that these vital signs of health — how strong a person is, the quality of their diet and how well their heart, circulation and lungs are working — are more predictive of risk of disease and death than how thin, or fat, a person is.

For example, a 2017 Dutch study followed overweight and obese people for 15 years and found people who were very physically active had no increased heart disease risk than ‘normal weight’ participants.

Getting Moving Is Important Advice

Physical activity has many benefits. Exercise can counter a lot of the negative behavioural and physiological changes that are occurring during midlife including for people going through menopause.

And, regular exercise reduces the tendency to use food and drink to help manage what can be a quite difficult time in life.

Measuring your waist circumference and monitoring your weight remains important. If the measures exceed the values listed above, then it is certainly a good idea to make some changes. Exercise is effective for fat loss and in particular decreasing visceral fat with greater effectiveness when combined with dietary restriction of energy intake. Importantly, any fat loss programme — whether through drugs, diet, or surgery — is also a muscle loss programme unless resistance exercise is part of the programme. Talking about your overall health with a doctor is a great place to start.

Accredited exercise physiologists and accredited practising dietitians are the most appropriate allied health professionals to assess your physical structure, fitness and diet and work with you to get a plan in place to improve your health, fitness and reduce your current and future health risks.

Prof ROBERT NEWTON, PhD, DSc, AEP, CSCS*D, FACSM, FESSA, FNSCA, is a Vice Chancellor’s Professorial Research Fellow and Professor of Exercise Medicine in the Exercise Medicine Research Institute at Edith Cowan University Perth, Western Australia. His current major research directions include: reducing decline in strength, body composition and functional ability in cancer patients; cancer-related fatigue and the influence of exercise; exercise medicine and tumour biology. Prof Newton has published over 1,000 papers including 530 refereed scientific journal papers, two books, 17 book chapters and has a current Scopus h-Index of 95 with his work being cited 33,500 times. In 2018, he was awarded the Cancer Council of Western Australian Career Achievement Award; in 2019, he was named the Western Australia Premier Scientist of the Year. As of 2024, his research had attracted over AUS$50m in competitive research funding. This article is republished from ©The Conversation [Good News: Midlife Health is About More Than a Waist Measurement. Here’s Why], under a Creative Commons License.

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