Daytime sleepiness is natural. Biologically, we all experience the effect of our ‘internal clocks’ and dips in our hormone levels that aid wakefulness, the largest daytime dip being around 3 pm. Some students offset the feelings of daytime sleepiness with caffeine. However, caffeine can have addictive side effects and if consumed late in the day, can be detrimental to restorative nighttime sleep. It is important to keep in mind that the best way to combat daytime sleepiness is to get sufficient nighttime sleep. But sometimes we all need that extra little boost of alertness during the midday dip. The following module will describe ways to help combat feeling sleepy during the day with activities that range from opening your window in the morning, to going on a run, or even just chewing some mint flavored gum!
Light and Sleepiness
Feeling groggy in the morning can make it difficult to get up and get going. Similar to a bedtime routine affecting the quality of your time asleep, morning light and temperature can have an effect on how drowsy you feel as you wake up. A study conducted in 2017 on female students measured the effects of varying temperature and light conditions on participants' wake up routine. The study found that participants felt more subjective sleepiness upon waking in dim light than in bright light, independent of temperature. Additionally, participants in warmer temperatures also reported higher levels of sleepiness and had the slowest reaction times on a vigilance task. The data was gathered from seeing how light and temperature interacted as well as their sole independent effects on sleepiness.
Te Kulve, M., Schlangen, L., Schellen, L., Frijns, A., & Van Marken Lichtenbelt, W. (2017). The impact of morning light intensity and environmental temperature on body temperatures and alertness. Physiology & Behavior, 175, 72-81.
Interestingly enough, bright light in the morning can also affect your hormonal state! A study conducted at the University of Chicago showed that a 3 hour exposure to bright light in the morning after sleep deprivation has a significant effect on hormones associated with feelings of drowsiness and our awakening response. After 36 hours awake, participants exposed to bright light in the morning had a decrease in melatonin (sleep inducing hormone) and increase in cortisol (stimulating hormone) (Leproult et. al, 2001). It should be noted that although cortisol is often associated with stress, it is a multifaceted hormone that helps regulate many important bodily functions. The HPA axis (hypothalamic-pituitary-adrenal axis) that produces cortisol, helps to regulate body functions ranging from sleep-wake cycles to stress, mood, digestion and immune function.
Leproult, R., Colecchia, E. F., L’Hermite-Balériaux, M., & Van Cauter, E. (2001). Transition from dim to bright light in the morning induces an immediate elevation of cortisol levels. The Journal of Clinical Endocrinology & Metabolism, 86(1), 151-157.
Another study found similar effects of light on cortisol levels of awakening participants. Participants were asked to wake up with either a regular alarm clock or a dawn simulator: an alarm clock that emits a light which increases in its brightness before sounding an alarm noise. By measuring saliva samples taken after participants had woken up, researchers found that cortisol was higher after awakening with the light emitting dawn simulator versus a regular alarm clock. This corroborates the finding that exposure to light during normal wake-up times increases a person’s awakening response.
Thorn, L., Hucklebridge, F., Esgate, A., Evans, P., & Clow, A. (2004). The effect of dawn simulation on the cortisol response to awakening in healthy participants. Psychoneuroendocrinology, 29(7), 925-930
Much like mere exposure to light in the morning, the type of light one is exposed to has the potential to enact hormonal changes as well. Researchers in the following study looked at the different physiological and psychological effects in college students of exposure to warm white light or blue-enriched white light in the morning. They found that blue-enriched white light decreases melatonin levels in the morning significantly more than the warm white light. Additionally, after exposure to blue-enriched white light participants felt less sleepy, rated their mood as higher, and experienced more visual comfort than warm white light. Cortisol levels did not differ significantly between the two light conditions. Thus, type of light, not just exposure to it in the morning, matters when trying to shake off some morning drowsiness.
Kyungah Choi, Cheong Shin, Taesu Kim, Hyun Jung Chung, & Hyeon-Jeong Suk. (2019). Awakening effects of blue-enriched morning light exposure on university students’ physiological and subjective responses. Scientific Reports, 9(1), 1-8.
Even in a sleep deprived condition, light can still help boost feelings of wakefulness. The power of the light-dark effects on our bodies is evident in these studies, thus managing the light conditions both at night (such as when we turn blue light off on our devices to allow melatonin to help ease us into sleep) and in the morning by allowing sunlight or other light conditions to help ease us back into a wakeful state. These hormones play a significant role in the sleep wake cycle, which is why one should aim to decrease exposure to light before they go to bed and increase exposure to light right after they wake up!
Physical Activity and Alertness
Another great way to decrease sleepiness during the day is to add some exercise to your morning routine. A correlational study using data from over 3,000 participants found the probability of feeling “overly sleepy” throughout the day decreased by a factor of .65 when participants exercised moderately for 150 minutes or vigorously for 75 minutes weekly. Concentration levels were also improved with physical activity. Participants who met the guidelines for weekly physical activity decreased the risk of having moderate-to-extreme difficulty concentrating by a factor of .45.
Loprinzi, P. D., & Cardinal, B. J. (2011). Association between objectively-measured physical activity and sleep, NHANES 2005–2006. Mental Health and Physical Activity, 4(2), 65-69.
Evidence for the causational relationship between physical activity and decreased daytime sleepiness has also been found. A 3-week study with a group of adolescents required one group to run for 30 min every morning at 7am while a control group simply woke up at 7am with no exercise. When looking at the change in each group over the course of the three week period, the running group’s subjective sleepiness decreased with time. It should be noted that a significant decrease of personal subjective sleepiness was the result of an interaction between type of group (running or control) and time (3 weeks). This suggests that one may only see the positive effects of decreased daytime sleepiness after implementing a morning physical activity routine for a longer period of time. If you are looking to incorporate a physical activity routine to help with sleep, try to keep up with it for at least 3 weeks to see (and feel) the range of benefits it may bring. Positive mood in the morning and sleep quality at night also increased for the running group. For more details, check out our physical activity and sleep module!
Kalak, N., Gerber, M., Kirov, R., Mikoteit, T., Yordanova, J., Pühse, U., ... & Brand, S. (2012). Daily morning running for 3 weeks improved sleep and psychological functioning in healthy adolescents compared with controls. Journal of Adolescent Health, 51(6), 615-622.
Chewing Gum and Alertness
Additionally, research has found that something even as small as chewing mint gum can increase alertness. After inducing a relaxed state by putting participants in a dark room for 11 minutes, researchers measured a participant’s sleepiness through a physiological measure of pupil oscillations as well as self-report. Those who were chewing gum during these 11 minutes reported significantly less sleepiness than the control group and had less pupil oscillation, indicating more alertness. Researchers from this study theorized that this could be due to an increase in brain activity caused by chewing gum or the alerting effects of mint. So try chewing some mint gum to help combat daytime drowsiness when sitting in a dark lecture hall, especially if your class is scheduled during the midday dip (from 1-3 pm)!
Johnson, Andrew J., Miles, Christopher, Haddrell, Ben, Harrison, Emily, Osborne, Liam, Wilson, Nigel, & Jenks, Rebecca. (2012). Effect of chewing gum on physiological and self-rated measures of alertness and daytime sleepiness. Physiology & Behavior, 105(3), 815-820.
These tips can help decrease drowsiness throughout the day, especially during circumstances when we don’t have a lot of control over our sleepiness, such as the midday dip or after an irregular night’s sleep. Yet, it can not be emphasized enough that the best way to decrease daytime sleepiness is to regularly sleep 7-9 hours every night. If you are having trouble scheduling a sufficient night’s sleep into your routine, check out the Time Management module for some helpful tips!
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