Question

Time Intervals	Body colour	Perspiration level	Body Temp (°C)	Breathing rate (breaths/min)	Heart rate (bpm)	Oxygen saturation (%)	Blood pressure (mmHg)
Resting (before exercise)	Normal	None	36.6 °C	24	71	100%	103/49
2 min	pink	Some	36.1°C	24	77	81%	116/53
2nd 2 min (4 min)	Red	Some	36.4°C	29	120	100%	135/64
3rd 2 min (6 min)	Red	A lot	36.1°C	39	150	91%	132/71
Resting for 4 min (After exercise)	Normal	Not sweating	36.8°C	21	94	97%	132/71

Why does an increased breathing rate accompany exercise? Why does an increased heart rate and blood pressure accompany exercise? What do both of these achieve? (Look at your second parameter(What is the second parameter? ) that did not change very much over time)

Answer 1

The table shows the how the body changes with exercise. There is increase in perspiration rate, breathing rate, heart rate and oxygen saturation.

With exercise there is increased breathing rate due to high rate of metabolism. The increased metabolic rate requires huge amount of oxygen which is provided by increase in rate of respiration. Since muscle cell respire more than they do when they are at rest so increased breathing rate makes sure that more oxygen is absorbed in the blood and more carbon dioxide is removed from blood. That's why increased breathing rate accompany exercise.

With exercise there is increase in heart rate and blood pressure. With exercise the muscles require more oxygen, three or more times as much as the resting muscle needs. The oxygen is transported to tissues by blood. So heart must transport more blood to the muscles. This is only possible when the heart pumps more blood i.e. Cardiac output should be increased. Cardiac output is the product of heart rate and stroke volume. So increase in heart rate increases the cardiac output which inturn transport more blood that supplies more oxygen to respiring tissues.

Cardiac output = heart rate × Stroke Volume

Increase heart rate

⬇️

Increase Cardiac output

⬇️

Supplies more oxygen to the tissues (muscles)

Blood pressure increases during exercise to increase the flow of oxygen rich blood throughout the body and mainly to the muscles.

Blood pressure = Cardiac output × peripheral resistance

During exercise the cardiac output is increased and peripheral resistance is decreased due to dilation of vessels. But increased cardiac out is more than the decrease in the total peripheral resistance. So the blood pressure rises.

The heart rate and blood pressure rises to pump harder and faster to circulate blood to deliver oxygen to the respiring muscles.

The second parameter from above i.e. the blood pressure donot rise so much because there is increase in cardiac output alongwith decrease in peripheral resistance. Increase in Cardiac output is more than decrease in peripheral resistance so blood pressure is increased but since one quantity is increasing and other is decreasing so the rise will not be much over time.

Also the body temperature doesn't change much over time. It is because during exercise the core temperature rises due to heat production but it is compensated by sweating (perspiration) and to skin and other body parts which leads to escape of heat from the body. So this parameter doesn't change much over time.