What's Causing Your Afternoon Tiredness?

Know the signs of a metabolic disorder

Tired woman with her eyes closed at her desk

Rafal Rodzoch / Getty Images

Anyone who is overworked or not getting enough sleep at night can feel tired toward the end of the day. The daily stresses of family, kids, commuting, and work mean it's not surprising that some days we just feel exhausted and ready for bed long before it's time. In mild cases of an afternoon slump, a good night's sleep and healthier eating can usually resolve the symptoms. But not all afternoon fatigue problems are so easily addressed. For a growing percentage of those who suffer from this issue, extreme tiredness could be a warning sign of a serious metabolic disorder.

Severe symptoms include a profound desire to sleep, muscle fatigue, sweating, shakes, headaches, changes in vision, or any combination of these. These symptoms are not signs of normal sluggishness but are often indicators of prediabetes, type 2 diabetes, or insulin resistance.

Sitting Disease

As more employees have become sedentary, the number of desk workers who develop "sitting disease" is on the rise. Sitting disease is a disorder that puts workers at an increased risk of prediabetes, type 2 diabetes, and cardiovascular problems.

Experts reported that even people who sit for extended periods but regularly hit the gym are at risk. Exercise in itself, though obviously critical to our bodies overall, doesn't seem to counter the damaging effects of all this time spent seated.

Without a whole-body and whole-day approach to health and physical activity, our bodies are at risk. You can combat sitting disease by finding ways to make even light activity or standing a regular part of your workday. Moving around the office, installing a standing desk, and eating protein instead of carbs are a few ways to combat the lethargy of sitting all day.

Still, it's important to be proactive if you notice unusual afternoon fatigue. There are many reasons people develop a sluggish feeling in the afternoon (and for some, the "afternoon" slump occurs in mid-morning). When symptoms worsen or become severe enough that they decrease your ability to complete tasks, you may want to seek advice from a physician to rule out certain health problems.


Prediabetes is a condition in ​which your body begins to suffer from changes in how it metabolizes carbohydrates. There are few early warning signs, so it is best to see a doctor if you are having severe afternoon slumps or have other risk factors associated with prediabetes.

Insulin resistance and metabolic syndrome (formerly called Syndrome X) are similar to prediabetes in that they are metabolic disorders that affect how the body metabolizes carbohydrates. Prediabetes, insulin resistance, and metabolic syndrome can all be early warning signs of type 2 diabetes. Type 2 diabetes is diagnosed when blood sugar levels are no longer in a normal or "prediabetic" range.

Insulin Resistance

Insulin is a hormone made by the pancreas. It acts as a key to open cells in the body and blood cells to allow energy (glucose) to enter. Without insulin, a person would die because their body would be unable to use the energy from the food they eat. When blood sugar builds up in the bloodstream, it can damage the organs and tissues in the body and brain and cause coma or even death if not treated.

If you have insulin resistance, your body resists the normal action of insulin. You might need to overproduce insulin to keep your blood sugars within a normal range, or you might not make enough insulin to keep your blood sugar in balance. Overproduction of insulin can cause fluctuations in blood sugar, weight gain, moodiness, changes in your menstrual cycle (for women), excess facial hair (women), skin tags, changes in skin color (dark, velvety patches called acanthosis nigricans), and periods of profound fatigue.

Insulin resistance is more common in people who also have severe allergies, thyroid disorders (especially Hashimoto's thyroiditis), polycystic ovarian syndrome (women), and can be caused by certain types of medications.

If your afternoon slump seems to be more than just occasional midday fatigue, it's important to discuss your symptoms with a doctor. Proactivity is the best way to head off any metabolic disorder.