Fatigue After Light Exertion

What Causes Fatigue After Slight Exertion?

Fatigue after slight exertion can have various causes, ranging in severity from 'minor' to 'generally fatal'.  Finding the true cause means ruling out or confirming each possibility – in other words, diagnosis.

Diagnose your symptoms now!
  • check your overall health status
  • let The Analyst™ find what's wrong
  • identify any nutritional deficiencies

Diagnosis is usually a complex process due to the sheer number of possible causes and related symptoms.  In order to diagnose fatigue after slight exertion, we could:

  • Research the topic
  • Find a doctor with the time
  • Use a diagnostic computer system.
The process is the same, whichever method is used.

Step 1: List all Possible Causes

We begin by identifying the disease conditions which have "fatigue after slight exertion" as a symptom.  Here are eight of many possibilities (more below):
  • Polymyalgia Rheumatica
  • Rheumatoid Arthritis
  • Hemochromatosis
  • Multiple Sclerosis
  • Male Menopause
  • Manganese Need
  • Pyroluria
  • Anemia

Step 2: Build a Symptom Checklist

We then identify all possible symptoms and risk factors of each possible cause, and check the ones that apply:
low hematocrit
very low sperm count
poor milk production
very slow fingernail growth
moderate alcohol consumption
joint pain/swelling/stiffness
morning stiffness for 45-120 minutes
numb/burning/tingling extremities
minor cold weather muscle spasms
recent onset neck pain
darker/redder skin color
being a recovered alcoholic
... and more than 70 others

Step 3: Rule Out or Confirm each Possible Cause

A differential diagnosis of your symptoms and risk factors finds the likely cause of fatigue after slight exertion:
Cause Probability Status
Hemochromatosis 97% Confirm
Anemia 22% Unlikely
Rheumatoid Arthritis 14% Unlikely
Pyroluria 1% Ruled out
Manganese Need 1% Ruled out
Male Menopause 0% Ruled out
Multiple Sclerosis 0% Ruled out
Polymyalgia Rheumatica 0% Ruled out
* This is a simple example to illustrate the process

Arriving at a Correct Diagnosis

The Analyst™ is our online diagnosis tool that learns all about you through a straightforward process of multi-level questioning, providing diagnosis at the end.

If you indicate being fatigued, The Analyst™ will ask further questions including this one:
Do you get tired easily, even with slight physical exertion?
Possible responses:
→ Don't know
→ No
→ Occasionally / moderately
→ Severely - almost any kind of activity tires me
Based on your response to this question, which may indicate no fatigue after slight exertion, fatigue after slight exertion or severe fatigue after slight exertion, The Analyst™ will consider possibilities such as:
Andropause/Male Menopause

Lethargy and lack of vitality are early signs that your anti-aging hormones (such as testosterone) are diminishing.


An inefficient pumping action by the heart can result in rapid fatigue.

Estrogens Low

Lethargy and lack of vitality are early signs that your anti-aging hormones (such as estrogen and progesterone) are diminishing.

Lupus, SLE (Systemic Lupus Erythematosus)

90% of patients with SLE experience fatigue.

Magnesium Requirement

Early symptoms of magnesium deficiency can include fatigue.

Multiple Sclerosis

Demyelinated nerve fibers use more energy to conduct impulses and thus fatigue more easily than normal fibers.  MS involves large numbers of nerve fibers in a state of borderline function, which suddenly turn off when the body temperature is elevated only one or two degrees.  The signals suddenly cease to be transmitted, and one has to stop.  Muscles that have been weakened result in a reliance on stronger muscles, which then tire faster.  One recent report indicates that for those with MS the energy cost of walking is two to three times that of a normal person over the same distance.  Such an increased use of energy obviously results in increased fatigue.  The fatigue of MS is hard to describe.

... and also rule out issues such as:
Concerned or curious about your health?  Try The Analyst™
Symptom Entry
Symptom Entry
Full Explanations
Optional Doctor Review
Review (optional)