Endurance is a component of physical fitness and is a measure of how much the body can exert itself during physical exercise over a prolonged period of time. Within fitness, endurance can be further broken down into cardiovascular endurance and muscular strength endurance.
Physical endurance is reliant upon various physiological factors that affect the body as age increases. Some of these factors may play a significant part in sports and performance. The below information outlines various factors that may contribute to a fall in endurance capabilities of the body during exercise. The information given is only a guide as various factors may influence endurance including genetics and training. Research is still ongoing to offer more precise data and information.
1. Aerobic Capacity – The body’s aerobic capacity falls with age due to the decline in maximum heart rate. (220 beats per minute minus age). Stroke volume is the amount of blood pumped out of the heart to the working muscles and tissues in one beat. Cardiac output is the total amount of blood pumped out of the heart within one minute. Therefore, stroke volume may remain at a high level but the cardiac output will plummet due to the inability of the heart to increase its rate compared to a younger athlete during endurance events.
2. Muscle Atrophy – Muscle atrophy is defined as a drop in muscle mass and size and is commonly observed following injuries where the body part has been immobilised in a cast for a period of time. Muscles are innervated by nerves called motor neurons. As age progresses, these motor neurons degrade and eventually die. This resultant loss of innervation results in a decline in muscle mass. Motor neurons may regenerate but usually not at a greater rate than cell death. The atrophy is usually identified from the age of 60 and normally affects fast-twitch muscle fibres at a greater rate. This explains why speed falls before endurance in athletes.
3. Muscle Glycogen – Muscle glycogen is stored within muscles and is an important fuel used during exercise. Therefore, glycogen stores within muscle tissue reduce as muscular atrophy increases with age. Most people become aware of this process once they become older as the ability to recover between training and exercise sessions fall. The recovery period post-workout is therefore prolonged until the muscles fully replenish themselves with glycogen reserves.
4. Arteriosclerosis & Atherosclerosis – Such terms relate to the narrowing and hardening of arteries in the body. Arteries transport blood away from the heart to the working muscles and due to age-related changes of the arteries, blood flow is reduced during exercise. This reduces the muscles endurance ability to continue at a relatively high exercise intensity level.
5. Cellular Activity – Mitochondria is a process whereby energy is generated through cellular activity. As age progresses, mitochondria and cells accumulate oxidative damage as a by-product of metabolism which ultimately reduces the efficiency of cellular activity and sports performance.
6. Hormonal Activity – A drop in testosterone and growth hormone levels reduces the ability of the body to recover following exercise. The ageing process experiences such effects and therefore sports and training performance will be affected.
Although much research suggests that age has a detrimental effect on endurance performance, other researchers support other concepts and report that age has either a minimal effect on endurance, endurance improves with age or no drastic change in endurance capabilities until the middle years (+/-50). Some authors state that VO2 max can be maintained to a high level up to the age of 49.
If you have any further questions regarding your training regimes or sports performance, please feel free to contact a member of our Manchester health and fitness team based in Didsbury.