Physiological changes during exercise


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Physiological changes during exercise

Cardiovascular system

Anatomy and physiology

Cardiovascular system anatomy and physiology

Lymphatic system anatomy and physiology

Coronary circulation


Blood pressure, blood flow, and resistance

Pressures in the cardiovascular system

Laminar flow and Reynolds number

Resistance to blood flow

Compliance of blood vessels

Control of blood flow circulation

Microcirculation and Starling forces

Cardiac output

Measuring cardiac output (Fick principle)

Stroke volume, ejection fraction, and cardiac output

Cardiac contractility

Frank-Starling relationship

Cardiac preload

Cardiac afterload

Law of Laplace

Cardiac and vascular function curves

Altering cardiac and vascular function curves

Cardiac cycle and pressure-volume loops

Cardiac cycle

Cardiac work

Pressure-volume loops

Changes in pressure-volume loops

Cardiovascular physiological responses

Physiological changes during exercise

Cardiovascular changes during hemorrhage

Cardiovascular changes during postural change

Auscultation of the heart

Normal heart sounds

Abnormal heart sounds

Myocyte electrophysiology

Action potentials in myocytes

Action potentials in pacemaker cells

Excitability and refractory periods

Cardiac excitation-contraction coupling


Electrical conduction in the heart

Cardiac conduction velocity

ECG basics

ECG normal sinus rhythm

ECG intervals

ECG QRS transition

ECG axis

ECG rate and rhythm

ECG cardiac infarction and ischemia

ECG cardiac hypertrophy and enlargement

Blood pressure regulation



Renin-angiotensin-aldosterone system


Physiological changes during exercise

USMLE® Step 1 questions

0 / 2 complete

High Yield Notes

6 pages


USMLE® Step 1 style questions USMLE

of complete

An athlete takes part in a 100-meter sprint and completes the race within 12 seconds. Via which of the following processes did the athlete’s muscles primarily generate energy during the race?  


Content Reviewers

Viviana Popa, MD


Jennifer Montague, PhD

Jung Hee Lee, MScBMC

Evode Iradufasha, MD

Rachel Yancey

During physical exercise, our organs and tissues are working hard to keep us moving; or, technically speaking, for our musculoskeletal system to do its job.

Now it’s fairly obvious that during exercise, skeletal muscles work, or contract, harder and faster than when we’re at rest, so they use a lot of energy in a short time, so they need a lot more blood and oxygen to keep going.

So organ systems like the cardiovascular and respiratory system have to make some quick physiological adjustments, to meet the skeletal muscles demand.

Moreover, the endocrine system also kicks things into high gear, by secreting hormones like cortisol and adrenaline, that speed up intracellular processes to keep us going.

But before we delve into the specifics of that, let’s remember how muscle contraction works on a microscopic level.

So, skeletal muscles are made up of muscle fibers which are actually the skeletal muscle cells.

We just call them “fibers” because they are long, multinucleated cells, meaning they have more than one nucleus.

Their structure also differs from other cells because their cytoplasm, sometimes also called sarcoplasm, is filled with stacks of long filaments called myofibrils, which are made up of contractile units called sarcomeres.

And finally, sarcomeres are made up of the thick myosin filaments, and thin actin filaments, which can slide over one another, shortening the sarcomeres.

So when all the sarcomeres in a muscle fiber do that in sync, that results in shortening of the muscle as a whole, or muscle contraction.

And this process is powered by energy in the shape of ATP molecules, where adenosine-triphosphate.

The three phosphates in the molecule are linked in a chain, and between two adjacent phosphate molecules, there are high-energy phosphate bonds.

ATP molecules attach to a part of the myosin filament called the myosin head.

The myosin head is actually an ATPase, or an enzyme that can cleave an ATP molecule into ADP and phosphate ion, releasing the energy stored in the bonds.

After the energy is released, ADP detaches from the myosin head, so myosin can bind to actin filaments, forming cross-bridges that result in shortening of the muscle fiber.


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  7. "Human Anatomy & Physiology" Pearson (2018)

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