Ever get that sleepy feeling around 3pm? You’re not alone, that’s your body’s circadian rhythm talking.
Most adults circadian rhythm dips and rises at two different times, so adults' strongest sleep drive generally occurs between 2:00-4:00 am and in the afternoon between 1:00-3:00 pm. There is some variation depending on the lifestyle choices of the individual, including sleeping and waking hours as well as eating habits. The sleepiness experienced during these dips may be more or less intense depending on whether they’ve had adequate sleep in previous days.
The circadian biological clock is controlled by a part of the brain called the Suprachiasmatic Nucleus (SCN), a group of cells in the hypothalamus that respond to light and dark signals. From the optic nerve of the eye, light travels to the SCN, signaling the internal clock that it is time to be awake. The SCN signals to other parts of the brain that control hormones, body temperature and other functions that play a role in making us feel sleepy or awake.
In the mornings, with exposure to light, the SCN sends signals to raise body temperature and produce hormones like cortisol. The SCN also responds to light by delaying the release of other hormones like melatonin, which is associated with sleep onset and is produced when the eyes signal to the SCN that it is dark. Melatonin levels rise in the evening and stay elevated throughout the night, promoting sleep.
In a perfect world we would sleep when it’s dark and wake when it’s light, providing our bodies with 8-10 hours of quality sleep per night. Unfortunately, for many people this is quite a challenge because of work, kids, school, etc. Adequate sleep is essential to overall health and that can not be emphasized enough. The impact of not getting enough sleep is no laughing matter.
Based on this study having a disrupted biological clock can promote weight gain of 10 pounds per year due to a decreased metabolic rate and slowed secretion of insulin. Thereby increasing health risk for type 2 diabetes and obesity. So the question is how do we avoid the side effects of a sleep deficiency or disrupted sleep cycle?
1. Aim for quality sleep by creating a ritual for yourself. Limit light exposure before bed (no TV, or computer screens) before bed, make sure your room is temperate (somewhere between 65-70 degrees) for optimal sleep.
2. Make sure your room is DARK and/or invest in a sleep mask. This will also be helpful in taking naps when your body really needs one. The best time to nap is between 1-3pm because of our circadian rhythm.
3. Avoid caffeine and alcohol in the evenings, when the effect of either wear off your body will wake you. “Alcohol consumption, in excess or too close to bedtime, diminishes the quality of sleep, often leads to more throughout the night, and time spent in REM sleep and slow wave sleep in the later part of the night, the deepest and most restorative phase of sleep.”
4. Exercise during the day to fatigue your body, most people find that on days they exercise they sleep better!
Life can make it challenging to get enough quality sleep, and if you can’t sleep “normal” hours because of work it can be very difficult to stay motivated to achieve your health and fitness goals. Implementing some of the above strategies can help you to prioritize getting more quality sleep and doing so should help you reach your goals with gusto! If you need more help talking through your sleep strategies let’s talk!