The Meaning of Fitness

by Jonathan Blood Smyth

In the springtime we all start thinking about how we could be slimmer, fitter and look better for the summer, if we haven’t already taken up a gym membership in January and let it lapse fairly quickly as the first flush of enthusiasm faded. Through all this most of us do not stop and think about what fitness actually means to us. Being fit is a desired state but this state is not defined and we have little idea what all the measurements of fitness mean, all of which makes it less likely that our rather vague plan will be ultimately successful. Physiotherapists may have a somewhat clearer grasp of some of the concepts but most will not be very precise.

Coronary heart disease is one of the most important mortality factors in society today, so the prevention and management of heart disease is a health priority. Risk factors for heart disease are well known so there is ample guidance as to how we can reduce our risks and brings the various measures closer to safe levels. Fitness is a complex of abilities which needs be individually worked on to achieve a useful functional balance. Leaving out one of the aspects of fitness can expose us to weaknesses and injury apart from not hitting our goals.

In aerobic fitness the body can keep up a level of performance for a significant period of time without tiring, perhaps to cycle continuously for an hour. The training effect level must be achieved for 15 to 20 minutes or improvements in capacity will not be reached.

To achieve muscular fitness we need to acquire sufficient strength and endurance in our muscles to achieve the forces and duration needed.

Flexibility of our body tissues involves all our joint and muscular structures having enough extensibility to safely perform the planned activities.

Balance is the ability of our bodies to maintain postural control in a wide variety of static and dynamic activities, enabling us to widen our ability to function.

Coordination is the ability to dynamically integrate power, endurance and balance into functionally useful movements to achieve our goals.

Health and fitness can be investigated by a variety of measurement techniques which indicate the status of particular body systems. Blood pressure measurements should be not more than one hundred and forty over ninety to be in the healthy range. The upper number indicates the aortic pressure during the ventricular pumping action known as systole (sist-oley) and the lower number indicates aortic pressure when the left ventricle is filling ready for the next pumping phase, i.e. during diastole (di-ast-oley). If the blood vessel walls are flexible they give under pressure, allowing that pressure to drop while stiffer vessel walls allow increased pressures throughout the system.

The consequences of high blood pressure or hypertension can lead to problems with kidney function, peripheral perfusion, and the chances of stroke and of heart disease. Cholesterol levels are also important in heart disease and are recommended to be less than five millimoles per litre, relating to the risks of developing heart disease and atherosclerosis. The relationship between our bodyweight and our height gives us a measure of healthy weight and body fat levels by a measure known as the Body Mass Index or BMI. The BMI poster indicates in coloured regions on the chart the areas of the graph which indicate the categories of obese, overweight, healthy or underweight.

From 20 to 24.9 are the recommended limits for a healthy body mass index and the chart allows the indication of a desirable weight for our size so we can plan a realistic bodyweight to aim for if we are overweight. There are some difficulties with the BMI in that some people, perhaps due to their structure or muscular bulk, seem to get unreasonable results for their predicted desirable weight. However, the body weight index does give a good indication of what a desired weight should be and can be used along with the desired body fat content of between 21 and 27%.

About the Author:
Jonathan Blood Smyth, editor of the Physiotherapy Site, writes articles about Physiotherapy, back pain, orthopaedic conditions, neck pain, injury management and physiotherapists in Kent. Jonathan is a superintendant physiotherapist at an NHS hospital in the South-West of the UK.