A marathon places enormous demands on the body, affecting everything from the heart and lungs to the muscles and energy stores. Over the course of 26.2 miles, the body undergoes a series of significant physiological changes, reports Independent
Your heart rate increases to deliver more oxygen
The heart works harder during a marathon to transport additional oxygen and nutrients to the muscles.
Breathing becomes faster
The body increases its breathing rate to bring more oxygen into the lungs and support the muscles during prolonged exercise.
The heart pumps more blood with each beat
The volume of blood pumped out by the heart rises to meet the body's increased demands.
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Dehydration can put extra strain on the cardiovascular system
Some runners experience an unusually large increase in heart rate during the race, which can be linked to dehydration and overheating.
Muscles are under constant stress
The quadriceps, calves, and hamstrings do most of the work, while the abdominal muscles and arms help maintain stability and forward movement.
Tiny muscle tears develop during the race
The repetitive impact and effort of running can cause microscopic tears in muscle fibers.
Muscle soreness may appear after the finish
These small tears can lead to delayed onset muscle soreness in the days following a marathon.
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The body generates large amounts of heat
A significant portion of the energy produced during running is released as heat rather than movement.
Sweating helps cool the body
As body temperature rises, blood flow to the skin increases and sweat production accelerates to help regulate temperature.
Fluids and electrolytes are lost
Heavy sweating causes the body to lose both water and important electrolytes throughout the race.
Energy demands rise dramatically
The body increases its metabolic activity to provide enough fuel for the entire marathon.
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The risk of hitting the wall grows late in the race
As glycogen stores become depleted and are not adequately replaced, many runners experience extreme fatigue and a noticeable drop in pace.
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