A structure in the heart that delays electrical impulses to allow the atria to contract before the ventricles.

The primary form of carbon dioxide transport in the blood, formed when CO₂ combines with water.

Blood pressure (BP) is the force exerted by blood on artery walls, measured in mmHg.

A part of the heart’s conduction system that transmits impulses from the AV node to the ventricles.

The volume of blood the heart pumps per minute.

Cardiovascular drift is the gradual increase in heart rate (HR) observed during prolonged submaximal exercise, typically when the body is exposed to heat or thermoneutral conditions.

The phase of the cardiac cycle when the heart relaxes and fills with blood.

Diastolic BP is the pressure during heart relaxation when the heart is filling with blood.

Gas exchange refers to the movement of oxygen into the bloodstream at the lungs and carbon dioxide out of the bloodstream for exhalation.

Hematocrit is the percentage by volume of red cells in your blood

An iron-rich pigment in red blood cells that binds oxygen in the lungs and transports it through the blood to the body's tissues, and helps return carbon dioxide to the lungs.

Heart rate is the number of times the heart beats per minute (bpm). It reflects how fast the heart pumps blood to meet metabolic demands.

The vein that carries absorbed nutrients from the small intestine to the liver for processing.

The heart’s natural pacemaker, responsible for initiating electrical impulses that regulate heartbeat.

Stroke volume (SV) is the amount of blood ejected from the left ventricle per beat (mL/beat).

The phase of the cardiac cycle when the ventricles contract to pump blood into the arteries.

Systolic BP is the pressure during heart contraction when the ventricles pump blood into the arteries.

The narrowing of blood vessels, directing blood to vital organs during stress or physical exertion.

The widening of blood vessels to increase blood flow and promote heat loss.

VO₂ max (maximal oxygen consumption) is the maximum volume of oxygen that an individual can use per minute during intense exercise.