Tea and Sleep


Last Updated: Nov. 8, 2011
Human and Cat Sleeping
Tea contains caffeine, which has been shown to interfere with sleep.[1] Caffeine is widely perceived to boost alertness and performance at various tasks, but a review of the scientific literature found that caffeine does not actually boost performance, but merely restores performance degraded by sleep loss.[1]

Consuming caffeine too close to bedtime can disrupt sleep, and insomnia and sleep loss can have major impacts on health and ability to function, including concentration, creativity, and immune system function. Michael J. Breus, WebMD's expert on sleep medicine, notes that caffeine can stay in your body's systems for up to 12 hours after consumption, and recommends avoiding caffeine within 4-6 hours of bedtime.[2]

Tea has benefits for sleep, especially over coffee

Sketch of a Sleepy Teacup
A study published in 2000 comparing coffee drinking to tea drinking found that while tea drinking leads to similar improvements in alertness throughout the day, tea drinking tends to disrupt sleep less than coffee drinking, possibly due to its significantly lower caffeine content.[3] Interestingly, tea seems to improve alertness as effectively as coffee, even with its lower caffeine content.[3]

Tea consumption may have some sleep benefits too. Certain teas have a high concentration of L-theanine, an amino acid which promotes relaxation and plays a role in healthy sleep.[4] One study found that the antioxidants in green tea may prevent some of the damage due to sleep apnea, a common sleep disorder, although it is not clear if tea has any potential to prevent or treat this disorder.[5]
Chamomile Blossoms
Chamomile
from Drink The Leaf

Herbal teas & sleep

Herbal teas, coming from many different plants, have diverse effects on sleep, with some disrupting it, some enhancing it, and many having little or no effect. Most herbal teas (with the notable exception of Yerba Maté and a few other herbal teas containing caffeine) are caffeine-free, making them a good choice to drink later in the day. However, herbal teas can contain stimulants other than caffeine, which can interfere with sleep.

Herbs that show potential to help improve sleep and/or treat sleep disorders include valerian and kava, which have been researched more extensively, and other herbs such as chamomile, lavender, hops, lemon balm and passionflower, for which more research is needed to draw conclusions.[6] Valerian and kava, however, are powerful drugs and are not necessarily safe for casual use as a beverage, whereas many other herbs like lemon balm and chamomile are generally safe to use in such a manner. Although its overall effects on sleep are inconclusive, chamomile, a favorite ingredient in teas consumed before bedtime, has been shown to promote relaxation.[7]

References:


1. Timothy Roehrs, Thomas Roth, Caffeine: Sleep and daytime sleepiness, Sleep Medicine, Vol. 12, No. 2, pp. 153-162, Apr. 2008.


2. Michael J. Breus, 12 Tips for Better Sleep in Bad Times, WebMD Health News, Oct. 4, 2001.


3. I. Hindmarch et. al. A naturalistic investigation of the effects of day-long consumption of tea, coffee and water on alertness, sleep onset and sleep quality, Psychopharmacology, Vol. 149, No. 3, Apr. 2000.


4. Russ Mason, 200 mg of Zen: L-Theanine Boosts Alpha Waves, Promotes Alert Relaxation, Alternative and Complementary Therapies, Vol. 7, No. 2, pp. 91-95, Apr. 2001.


5. Kelli Miller Stacy, Green Tea Puts Sleep Apnea Woes to Bed?, WebMD Health News, May 16, 2008.


6. Charlotte Gyllenhaal et. al., Efficacy and safety of herbal stimulants and sedatives in sleep disorders, Sleep Medicine Reviews, Vol. 4, No. 3, pp. 229-251, Jun. 2000.


7. Moriya Kiyoshi et. al. Correlation between the indices of autonomic nervous system and mood after drinking chamomile tea. Japanese Journal of Biofeedback Research, Vol. 28, 2001.



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