Reactive Hypoglycemia or Afternoon Slump?

Is low blood sugar causing your afternoon fatigue?

Businesswoman asleep at desk next to cup of coffee
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If you feel great outside the workplace, but your energy fades as the day wears on at work, you may be experiencing a common workplace effect known as "afternoon slump." Its causes are many: being inside an office building without natural ventilation and natural light, sitting at a computer all day, or your lunch choices are just a few culprits. Either way, the result is a general feeling of malaise or fatigue. Dr. Sally Norton describes the afternoon slump as "a wave of tiredness, a loss of concentration and the seemingly impossible battle to keep your eyes open."

Afternoon slump affects most people in the mid-to-late afternoon, usually around 3 p.m., though it can also hit workers at mid-morning. Simple changes in your routine and diet may be enough to end afternoon slump for good. Sometimes, however, there are deeper underlying health causes to address.

Severe Slump

Severe afternoon slump shouldn't be dismissed as an ordinary and expected part of your workday. Extreme fatigue, especially when shakiness, dizziness, or sweating are present, could be a warning sign of reactive hypoglycemia.

Severe slump symptoms include an intense desire to sleep, muscle fatigue, sweating, shakes, headaches, changes in vision, or any combination of these symptoms. These symptoms are not signs of normal sluggishness that can occur in mid-morning or the afternoon. If these symptoms 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 that can cause afternoon slump.

Reactive Hypoglycemia: What Is It?

Hypoglycemia means low blood sugar (blood glucose). Many things can cause it, including metabolic problems, medications, and insulin resistance. Reactive hypoglycemia occurs in response to some trigger, usually after eating. It occurs in people who don't have diabetes but may sometimes also occur in people who have Type 2 diabetes. Suspected triggers for reactive hypoglycemia include:

  • Sensitivity to stress hormones
  • Insufficient glucagon production (glucagon is the counter hormone to insulin—insulin lowers blood sugar and glucagon raises it)
  • Enzyme deficiencies
  • Overproduction of insulin after eating

Reactive hypoglycemia can also start to occur in patients after gastric bypass surgery and is more common in young children than in adults. It can be an early sign of diabetes.

Hypoglycemia Symptoms

Hypoglycemia causes different symptoms of varying degrees in people. Some people lack "hypoglycemia awareness," meaning that cannot feel that their blood sugar has dropped. Here are common symptoms people experiencing low blood sugar may feel or exhibit:

  • Hunger or nausea
  • Shakiness and weakness
  • Nervousness and anxiety
  • Sweating or clammy hands, face, and forehead
  • Dizziness or lightheadedness
  • Headache and/or stomach ache
  • Sleepiness (and disrupted sleep at night)
  • Mental confusion
  • Irritability, crying, or mood swings
  • Difficulty speaking—extreme lows can cause slurred speech
  • Feeling like you might pass out or an intense urge to sleep

It's normal to occasionally feel sluggish in the afternoon, especially if you're under a lot of stress, not eating properly, or not getting enough sleep. But if you have any of the above symptoms, you may want to talk with your doctor about ruling out reactive hypoglycemia. Even if it's not a blood sugar issue, you can find ways to treat your symptoms and get through the afternoon without the urge to nap at your desk.

Disclaimer: This information is not intended to diagnose or treat any medical condition and should not be used as a substitute for medical advice from a licensed health professional. If you suspect you may have problems with low blood sugar, call your doctor immediately.