Taking a nap is almost like an extreme sport; you know what time you go to bed but not what time you get up. Unless you are a professional napper, you might experience somewhat unpleasant awakenings and find yourself even more tired than before sleeping. Science has an explanation for this and it’s called sleep inertia. According to the sleep specialist at the Mayo Clinic in Scottsdale, Arizona, Dr. Waiz Wasey, this symptomatology is called ‘post-nap flu’, and several factors contribute to it.
Sleep cycles last 90 minutes and have three stages. At night, we can complete 3 or 4 of these cycles, but during a nap, we usually do not, especially if it is a short nap (although that doesn’t exist in Spain). Symptoms such as vomiting, panic attacks lasting half an hour or even up to 6 hours can be experienced. The situation can be even more unpleasant for those who have sleep apnea, experiencing headaches, dizziness, and nausea. The quality of the nap also depends on factors such as diet.
Experts recommend avoiding fatty or acidic foods to prevent acid reflux, and emphasize the importance of staying hydrated and avoiding fried foods, dairy, or too much fiber. If possible, experts recommend not sleeping during the day. If that is not feasible, naps of 20 minutes or, alternatively, 90 minutes are recommended. This way, you will avoid breaking a sleep cycle and the REM phase with a short nap, or you will allow yourself to start and finish the cycle with a longer one.
But first, siesta
One of the best Spanish inventions that has globalized (with all the sense in the world) is taking a siesta. A nap in the middle of the day that allows us to continue with energy and eagerness, but is it always like this? Many people experience unpleasant symptoms after napping and feel even worse than before sleeping. Experts call it ‘post-nap flu,’ and it has to do with sleep inertia.
What happens to our body when we take a nap?
The sleep specialist at the Mayo Clinic in Scottsdale, Arizona, Dr. Waiz Wasey, explains that “There are several reasons behind this so-called ‘post-nap flu,’ and it is not caused by a single factor.” A sleep cycle lasts approximately 90 minutes, during which the three stages of sleep are reached, including the REM phase. When we sleep through the night, we can complete 3 to 4 full cycles, depending on the hours of sleep. However, naps do not last the same amount of time, so many times a complete cycle is not finished. It is precisely this that causes unpleasant awakenings, which is referred to as sleep inertia.
What symptoms can appear?
Experts explain that symptoms can last anywhere from half an hour to even 6 hours, depending on the case, and can include vomiting or panic attacks. The situation is even worse for those who experience sleep apnea, as Dr. Wasey explains, ‘Interruptions in breathing can lead to drops in oxygen levels that can trigger headaches, dizziness, and nausea.’ Another possible symptom is related to nutrition, which is acid reflux. For this reason, it is recommended to avoid acidic or fatty foods, in addition to monitoring the diet by eliminating fried foods, excess dairy, or too much fiber, and prioritizing hydration.
How to take an optimal nap?
To avoid experiencing a bad wake-up and suffering from these temporary symptoms, experts recommend two options: taking a 20-minute nap that does not start the sleep cycle, or a 90-minute nap that begins and completes the cycle without interrupting it. This way, the sleep cycle is respected without experiencing an unpleasant awakening, and one can have a fully restorative sleep.