When you wake up, it takes some time to get the electrolytes flowing through the muscles in your hands again. That’s why you may not be able to make a fist right after waking up. This effect is more pronounced if you don’t wake up naturally.
Balling up your palm and making a fist is easy enough, right? But try doing that right after you’ve woken up from a deep sleep. It’s highly likely that you will be able to. It’s a simple enough task, yet incredibly difficult to complete immediately after pulling out of slumber. Why is that?
As it turns out, there are a couple reasons behind this strange bodily phenomenon.
(Note: this is not a universal thing; not everyone experiences difficulty clenching their palms in a fist right after waking up. Also, this little symptom might be a sign of a more serious condition that requires medical attention.)
The role of electrolytes in muscle engagement
For a muscle to contract, two basic ingredients are needed—a nerve impulse (or an electrical signal from a nearby nerve) and electrolytes. Electrolytes are minerals that carry an electric charge when they’re dissolved in a liquid. Common electrolytes include potassium, calcium, sodium and bicarbonate.
A muscle needs calcium, potassium and sodium to contract. Now, when a nerve signal is sent (to contract a muscle), calcium enters the muscle in question on a cellular level, and potassium exits. However, when the muscle needs to relax, it only needs potassium. That’s why a lack of potassium causes such nasty muscle cramps.
Reduced brain and heart activity during sleep
When you sleep, your body relaxes completely and begins to heal itself. Your brain waves slow down too, or, in other words, the brain relaxes. Your heart rate decreases as well. You see, when you’re moving around constantly or generally physically active during your waking hours, the heart has to pump blood quickly so that all the vital organs of your body function efficiently. However, when you are in a deep sleep, you don’t do much moving around (unless you’re Wolverine, of course!).
Without any physical movement, the heart rate drops during sleep. This heart rate is enough to keep the blood flowing throughout the body, but not nearly as efficiently as if you were awake. Thus, the body decides which parts need the most oxygen and electrolytes, and reduces the flow of electrolytes to muscles in the limbs. Since you’re sleeping, you don’t even realize that it’s happening.
However, the moment you wake up, all systems are a go at once! Your brain, heart and the rest of the body start to resume their “waking hours” duties, but this doesn’t happen instantly. It takes some time to get the electrolytes flowing through the muscles in your hands again. That’s why you may not be able to make a fist right after waking up. This effect is more pronounced if you don’t wake up naturally.
If you wake up in response to an emergency (like a fire or some other danger), the dynamics change. In that case, your body releases adrenaline and you acquire all the strength you need to rapidly deal with that “fight or flight” situation.
Sign of a medical condition?
Many people experience this weird sensation of not being able to make a fist just after waking up; it’s a perfectly natural thing to experience. However, if it appears suddenly, without warning, or keeps getting worse over time, it could be a symptom of an underlying medical condition, such as rheumatoid arthritis or Lambert Eatons syndrome.
In other words, if you’ve never experienced this sort of hand weakness before, and you suddenly do, it’s best to consult a doctor and get it checked out.
- Harvard University (Link 1)
- Harvard University (Link 2)
- University Of North Texas
- Oregon State University