Lifestyle changes can help fight sleep inertia
Q: I recently heard on social media about something called sleep inertia. It came up in a conversation about how to get a better night’s sleep. Is this real, or was it invented? I often don’t feel refreshed when I wake up and wonder if sleep inertia might be why.
A: While sleep inertia sounds like one of the health memes that trend on social media, in fact, it is a real thing. The name refers to the persistent grogginess that sometimes occurs upon awakening. It’s a temporary state and typically subsides within 30 minutes or so. Sometimes, though, it can take a few hours to shake off.
When someone has sleep inertia, they awaken feeling thick, fuzzy and out of sync. They often find their cognitive abilities are slower than usual. The intensity and duration of the symptoms can vary. It is known to be more pronounced among night-shift workers, teenagers and people who already have a significant sleep debt.
The reasons this transitional state occurs are not yet fully understood. However, brain scans of individuals experiencing it show that some of the features associated with sleep persist, despite the person being awake. An important factor in both the likelihood of it occurring and the intensity of an episode is the person’s sleep stage at the time of awakening. Sleep inertia is far more likely when someone is suddenly yanked out of what is known as slow-wave sleep. That’s the deep and restorative phase of the sleep cycle. If your alarm clock goes off while you’re in stages 1 or 2 of sleep, which are light sleep, the transition to wakefulness is usually smoother.
Fluctuations in core body temperature are also part of the nightly sleep cycle. Sleep inertia tends to be more intense when waking coincides with lowest point of that temperature shift. Other contributing factors include being out of sync with your circadian cycle, having an underlying medical condition and the use of certain medications.
In addition to being unpleasant, sleep inertia can impair thinking and decision-making, adversely affect learning and short-term memory and lead to slower reaction time. Someone experiencing sleep inertia should try to give themselves extra time for the effects to fade before performing critical tasks.
Research shows that certain strategies can minimize the chances of a groggy wake-up. For people who nap, keep them short, in the range of 10 to 15 minutes. Any longer and you risk waking in the deeper part of the sleep cycle.
Bright light suppresses melatonin, the so-called sleep hormone. Exposure to bright light upon awakening can speed recovery from an extended episode of sleep inertia. However, the same effect isn’t seen in briefer episodes. Caffeine has been shown to lessen recovery time from all forms of sleep inertia. Regular sleep habits, with a consistent bedtime and waking time, are also important. There is also evidence that repeated use of the snooze button in an effort to prolong sleep can backfire and bring on an episode of sleep inertia. If morning grogginess is persistent and interferes with quality of life, it’s a good idea to talk to your doctor.
Assess health via grip strength
Q: I am a 46-year-old woman, and I recently moved to be closer to my family. I have a new doctor who surprised me by talking about grip strength. She said it’s an important measure of health. I have never heard of this. Can you explain?
A: Grip strength refers to the power generated by the muscles of the hand and the forearm. They work together in actions such as grabbing, pressing, crushing, rotating and pinching. Grip strength plays a direct role in someone’s ability to hold, pull, lift or heft an object, and it dictates how heavy that object can be. It also comes into play in a dynamic setting, with actions as varied as opening a jar, throwing a ball, pulling weeds, carrying a grocery bag, holding onto a handrail or hanging from a chin-up bar. The measure of grip strength includes the amount of pressure someone can exert and the length of time they can sustain it.
Considering the many ways we use our hands, it is easy to see how this type of strength affects every aspect of daily life. But research shows that grip strength is also an important measure of overall health. In adults of all ages, it has been found to be a reliable predictor of muscle strength, muscle mass, bone mineral density and nutritional status. In older adults, grip strength is used as an indicator of vitality, and as an accurate predictor of a decline in physical and mental function.
Research continues to link a decline in grip strength to a range of adverse health issues, including heart disease, arthritis, osteoporosis, Type 2 diabetes and certain cancers. It has also been found to be a predictor of the likelihood of post-surgical complications, post-surgical recovery time and mortality. This has led grip strength to be considered an important biomarker when assessing health, particularly in older adults. At the same time, it is important to understand that, while it can be an indicator, grip strength alone is not a symptom.
Hand exercises can improve grip strength. These include squeezing a tennis ball, wringing out a wet towel, hanging from a pullup bar, lifting a weight with pinched fingers and carrying dumbbells as you walk. These work various combinations of muscle groups and improve your crush, pinch and support grips. The dominant hand also plays a role. Right-handed people tend to have weaker grip strength in their left hand. The reverse is true in those who are left-handed. Interestingly, this strength disparity turns out to be less pronounced in left-handed individuals.
Grip strength is also an indicator of someone’s general strength and fitness. That means strength, stretch and aerobic exercise translate into this metric. Lifting weights, which can be an important component of staying fit, involves and improves grip strength. So do whole-body exercises such as running, yoga, swimming and cycling. Even household tasks such as gardening, sweeping, cooking, running a vacuum or hand-washing the dishes can contribute to grip strength. Once you become aware of this very specific aspect of fitness, it becomes easy to focus on maintaining and improving it.
• Dr. Eve Glazier is an internist and associate professor of medicine at UCLA Health. Dr. Elizabeth Ko is an internist and assistant professor of medicine at UCLA Health. Send your questions to askthedoctors@mednet.ucla.edu.