Flabby guts and arteries 2024

 

Flabby guts and arteries 2024

Why we need to look after Smooth Muscle

What is smooth muscle?

We have three distinct types of muscle: skeletal, cardiac and smooth. All three are connected to the nervous system: skeletal muscle is under conscious control, cardiac and smooth muscle are not. The latter two are largely automatic but can and do respond to sensors (receptors) connected to the nervous system. We are conscious of  skeletal and cardiac muscle activity but largely and sometimes entirely, unaware of smooth muscle and its activities.

Where is smooth muscle found?

Smooth muscle is found in the circulatory system particularly arteries; throughout the digestive system; in the urino-genital system; the reproductive organs;  the eyes and lungs. In other words, it’s the most widespread and unappreciated of all our musculature.

Briefly here are some of the functions for different tissues performed automatically by smooth muscle:

Arteries: SM enables the artery to change its internal diameter. When relaxed the artery is wider and vice versa. This has a direct effect on blood pressure and the distribution of blood to organs such as skin, heart, liver as well as  skeletal muscle.

Gut ( alimentary canal): The gut has smooth muscle along its entire length. SM waves of contraction (peristalsis) move food and liquids in a ‘mexican wave’ fashion through the gut from swallow to defecation. It is so effective we can even drink fluids standing on our head! SM provides the no-return valves (sphincters) on entry and exit to the stomach as well as the anus and finally powerful SM allows the stomach to wring and churn food into a liquid digestible state called chyme. 

Eyes: Our eyes have smooth muscle to alter the shape of the lens allowing us to focusnear and far using circular (ciliary) muscles which when relaxed pull the lens into a flatter shape for long distance and when contracted allow the lens to round up enabling closer focus. Muscles in the iris open and reduce the pupil letting more or less light into the eye.

Bladder: the bladder is a sheet of smooth muscle which enables us to empty the bladder when the stretch receptors tell us it is full.

The above is by no means a complete list but it serves to give a sense of the range of vital but unconscious activities on which we depend.

Conditioning Smooth Muscle, can they get flabby ..is it a real thing?

‘Health-aware’ folk take care of their skeletal and cardiac muscle through exercise and diet but they do not, at least do not deliberately, take care of smooth muscle. Does this matter? If smooth muscle can look after itself in pretty much any scenario then the answer is ‘no’; if smooth muscle, like other muscle is vulnerable to the ‘life-style’ of an individual then it does matter. 

Contemporary First World life can be usefully characterised by its environment, activity and diet. For a great many this means living in a largely temperature and light controlled environment; being for the most part sedentary; being medicated for blood pressure and cholesterol levels and finally eating mostly UPF (ultra-processed food). What this means really is that variation (in diet, activity, light, temperature) has been replaced by constant. Unfortunately for us, smooth muscle is conditioned ( or exercised) by variation; variation that was once so normal as to be sufficient to put smooth muscle onto ‘automatic’ and allow us to ignore it. No more I fear is this the case.

Variation versus Constant

This is the point of the post. Smooth muscle has an easy time of it nowadays. 

Consider the gut first: modern food is mostly cooked, processed,  soft, pulped,  predigested, emulsified. The gut has very little work to do compared to working with food of the recent past. IBS, Crohns and reflux are common complaints.

The variation on arterial pressure and diameter is minimised if a life style is sedentary, temperature controlled and  medicated with blood pressure controlling drugs. Atherosclerosis or as it was called, hardening of the arteries, is a classic 21st century pathology.

Eyes too do not get a work out when living in permanent near constant daylight and with focal distances ranging from a computer screen to the office wall. 

Even the bladder does not escape with access to ‘comfort breaks’ being the norm.

My hypothesis is simple. Smooth muscle needs exercise to remain strong and healthy just like any other muscle. Today, for many, it does not get the variation it needs to stay fit. Gut and arterial diseases will have a component that is a direct consequence of flabby smooth muscle.