Physiological factors which can affect sport and exercise

A) Environment

A definition for environment; the aggregate of all external and internal conditions (such as temperature, humidity, radiation, magnetic and electric fields, shock vibration, etc.) either natural or man made, or self-induced, that influences the form, performance, reliability or survival of an item.

Altitude

As altitudes increases air density decreases progressively, at sea level barometric pressure averages around 760mm Hg, at 5500m above sea level the pressure is about half that. Relatively small decrease in barometric pressures exerts little affect on a person during rest or even mild exercise, but performance in vigorous aerobic activities greatly decreases. The poor performance of athletes in the 1968 Olympics in Mexico City was caused by the reduction of oxygen in the air (due to the altitude). And the body unable to meet the demands for oxygen, But altitude does not affect anaerobic activities as oxygen does not get utilised.

With lower amount of oxygen in the air at altitude it is possible to suffer illnesses such as Acute Mountain Sickness (AMS) which represents the body’s intolerance of the hypoxic (low oxygen) environment at one’s current elevation. High Altitude Cerebral Edema; this is when the brain swells and ceases to function properly. High Altitude Pulmonary Edema, fluid in the lungs.

Depth

Water pressure also has an effect on the physiological functions of the body; Stafford-Brown et al states that when a person is submerged, their resting heart rate will decrease. This is attributed to the pressure of the water on the body producing central pooling of the blood. This extra pressure acts to increase the rate of blood returning to the heart, which will result in an increased stroke volume. This in turn producing a lower hear rate.

We can dive up to about 10 metres before the body will start to feel any discomfort. But with training people have been able to free dive 100m and more! If the face is submersed in cold water it triggers a vasoconstriction process were the blood flow from the periphery goes to the central nervous system and vital organs. Therefore most of the blood flow is going to the vital organs and reducing the metabolic rate. A trained diver can reduce their bradycardia (vasoconstriction) by up to 50% so if their resting heat beat was 75 beats per minutes (bpm) it would become 37bpm

Cold-

How cold climates affect the body depends greatly on how cold the environment is. During exercise it can actually have a positive effect on performance, as the cardiovascular system no longer has to divert blood to the periphery for heat loss, so it can supply the muscles with extra blood containing nutrients. However, exposure to extremely cold environments which involve sports such as skiing and mountain climbing can cause the body’s core temperature to drop below normal and cause hypothermia. So the body has to gain heat in order to survive, the body attempts to prevent heat loss as well as to increase heat production.

Hot

The effects that hot climates have on the body are peripheral dilation of blood vessels which is affected by the autonomic nervous system upon detection by the thermal centre in the hypothalamus of an increase in core temperature. Warm blood is brought to the under surface of the skin, thus increasing the temperature gradient and encouraging convection of heat from the blood. This increase in peripheral blood flow causes an increase in the venous return to the heart, which in turn causes the heart rate to increase and a rise in cardiac output. Renal blood flow is reduced due to the sympathetic response and can lead to further complications. More serious effects can result in athletes suffering from heat illnesses such heat stroke. These include hematuria, myoglobinuria, clotting abnormalities and hepatic damage to name a few.

B) Gender

The primary difference between males and females is the male sex hormone testosterone. Although this hormone is present in females, the much larger amounts in male’s accounts for the male primary and secondary sexual characteristics including body fat and muscle mass.

Testosterone is what makes male’s masculine, on the opposite females develop ovaries, which produce oestrogen leading to the development of female characteristics.

It is these differences in hormones which lead to the differences between males and females, these can be summarised as;

Physical size

Women in general tend to be physically smaller than men and have less muscle mass. This difference in size affects the absolute amount of physical work that can be performed by men and women. The lung capacity of men is 25 to 30 percent greater than that of women. This gives men still another advantage in the processing of oxygen and in doing aerobic work such as running. Women have less bone mass than men, but their pelvic structure is wider. This difference gives men an advantage in running efficiency.

Body fat percentage

Women carry about 10 percentage points more body fat than do men of the same age. This gives women greater buoyancy in water which makes them better suited to swim the channel. Men accumulate fat primarily in the back, chest, and abdomen; women gain fat in the buttocks, arms, and thighs. Also, because the center of gravity is lower in women than in men, women must overcome more resistance in activities that require movement of the lower body.

Effects of exercise

The average woman’s heart is 25 percent smaller than the average man’s. Thus, the man’s heart can pump more blood with each beat. The larger heart size contributes to the slower resting heart rate (five to eight beats a minute slower) in males. This lower rate is evident both at rest and at any given level of sub-maximal exercise. Thus, for any given work rate, the faster heart rate means that most women will become fatigued sooner than men.

C) Race

It is clear that certain races are better suited to certain sports. African athletes dominate both short and long difference running events, throwing and swimming events are dominated by white athletes. Asians will flourish in diving, gymnastics and table tennis, while Indians are good at field hockey.

West African

These athletes have dominated the explosive sprint events, the fastest 200; 100m times are all by black athlete. Research suggests that these athletes have;

* Lower body fat

* Longer legs

* Narrow hips

* Greater muscles mass

* Higher bone mineral density

* Higher levels of testosterone

* Higher percentage of fast twitch fibres

These factors suggest that West African athletes are better suited to sprinting than long distance running.

East African

These athletes have dominated the middle/long distance running events for some time. The top 60 times for the 3000m steeplechase are all held by Kenyan athletes. The vast majority of top Kenyan runners live in a region that is at high altitude, this has lead scientists that their adaptation to living at high altitude has given them an increased athletic prowess at endurance events.

Although east Africans are fanatic about football they are among the worst in the world, this is because of their physiology.

Genetical make-up plays apart in their running success- they are ectomorphs, short and very slender with;

* Huge natural lung capacity.

* High slow twitch muscle fibre percentage.

* Have a greater number of red blood cells

* More energy producing enzymes in muscles

Caucasian athletes

The body type of whites falls in between west and east African athletes. They tend to have more natural upper body strength as they have a mesomorphic body type. White athletes tend to dominate strength sports such as throwing and weightlifting.

Also whites tend to dominate swimming; African athletes are thought to have heavier bones and smaller chest cavities, which affect their buoyancy.

D) Physiological aides

Athletes can take drugs for several reasons. An athlete may want to:

* Build mass and strength of muscles and/or bones

* Increase delivery of oxygen to exercising tissues

* Mask pain

* Stimulate the body

* Relax

* Reduce weight

* Hide use of other drugs

Different drugs and their effects

One of the more commonly used drugs is steroids. Steroids are drugs derived from hormones. Anabolic steroids are one group of these drugs.

Anabolic steroids – or more precisely, anabolic/androgenic steroids – belong to a group known as ergogenic, or so-called ‘performance-enhancing,’ drugs. They are synthetic derivatives of testosterone, a natural male hormone. ‘Anabolic’ means growing or building. ‘Androgenic’ means masculinizing or generating male sexual characteristics.