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 mid-life 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 ageing parents) is when 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 mid-life. 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 program. 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 program – whether through drugs, diet or surgery – is also a muscle loss program unless resistance exercise is part of the program. 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.

Rob Newton, Professor of Exercise Medicine, Edith Cowan University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Can you imagine hearing yourself speak? A voice inside your head – perhaps reciting a shopping list or a phone number? What would life be like if you couldn’t?

Some people, including me, cannot have imagined visual experiences. We cannot close our eyes and conjure an experience of seeing a loved one’s face, or imagine our lounge room layout – to consider if a new piece of furniture might fit in it. This is called “aphantasia”, from a Greek phrase where the “a” means without, and “phantasia” refers to an image. Colloquially, people like myself are often referred to as having a “blind mind”.

While most attention has been given to the inability to have imagined visual sensations, aphantasics can lack other imagined experiences. We might be unable to experience imagined tastes or smells. Some people cannot imagine hearing themselves speak.

A recent study has advanced our understanding of people who cannot imagine hearing their own internal monologue. Importantly, the authors have identified some tasks that such people are more likely to find challenging.

What the study found

Researchers at the University of Copenhagen in Denmark and at the University of Wisconsin-Madison in the United States recruited 93 volunteers. They included 46 adults who reported low levels of inner speech and 47 who reported high levels.

Both groups were given challenging tasks: judging if the names of objects they had seen would rhyme and recalling words. The group without an inner monologue performed worse. But differences disappeared when everyone could say words aloud.

Importantly, people who reported less inner speech were not worse at all tasks. They could recall similar numbers of words when the words had a different appearance to one another. This negates any suggestion that aphants (people with aphantasia) simply weren’t trying or were less capable.

A welcome validation

The study provides some welcome evidence for the lived experiences of some aphants, who are still often told their experiences are not different, but rather that they cannot describe their imagined experiences. Some people feel anxiety when they realise other people can have imagined experiences that they cannot. These feelings may be deepened when others assert they are merely confused or inarticulate.

In my own aphantasia research I have often quizzed crowds of people on their capacity to have imagined experiences.

Questions about the capacity to have imagined visual or audio sensations tend to be excitedly endorsed by a vast majority, but questions about imagined experiences of taste or smell seem to cause more confusion. Some people are adamant they can do this, including a colleague who says he can imagine what combinations of ingredients will taste like when cooked together. But other responses suggest subtypes of aphantasia may prove to be more common than we realise.

The authors of the recent study suggest the inability to imagine hearing yourself speak should be referred to as “anendophasia”, meaning without inner speech. Other authors had suggested anauralia (meaning without auditory imagery). Still other researchers have referred to all types of imagined sensation as being different types of “imagery”.

Having consistent names is important. It can help scientists “talk” to one another to compare findings. If different authors use different names, important evidence can be missed.

We have more than 5 senses

Debate continues about how many senses humans have, but some scientists reasonably argue for a number greater than 20.

In addition to the five senses of sight, smell, taste, touch and hearing, lesser known senses include thermoception (our sense of heat) and proprioception (awareness of the positions of our body parts). Thanks to proprioception, most of us can close our eyes and touch the tip of our index finger to our nose. Thanks to our vestibular sense, we typically have a good idea of which way is up and can maintain balance.

It may be tempting to give a new name to each inability to have a given type of imagined sensation. But this could lead to confusion. Another approach would be to adapt phrases that are already widely used. People who are unable to have imagined sensations commonly refer to ourselves as “aphants”. This could be adapted with a prefix, such as “audio aphant”. Time will tell which approach is adopted by most researchers.

Why we should keep investigating

Regardless of the names we use, the study of multiple types of inability to have an imagined sensation is important. These investigations could reveal the essential processes in human brains that bring about a conscious experience of an imagined sensation.

In time, this will not only lead to a better understanding of the diversity of humans, but may help uncover how human brains can create any conscious sensation. This question – how and where our conscious feelings are generated – remains one of the great mysteries of science.

Derek Arnold, Professor, School of Psychology, The University of Queensland

This article is republished from The Conversation under a Creative Commons license. Read the original article.