Why does coffee help us start the day?
Caffeine is a tricky substance. To our brains, caffeine looks like adenosine, a compound consisting of adenine (one of the four building blocks of DNA) and ribose. As it is created in the brain, adenosine binds to the adenosine receptors, causing drowsiness by slowing down nerve cell activity.
Caffeine is called an adenosine receptor antagonist because it causes the adenosine receptors to no longer recognize adenosine and so nerve cell activity speeds up. It also causes blood vessels to dialate, most likely to get more oxygen to the brain during sleep. When we drink coffee, the caffeine binds to the adenosine receptors instead, causing an entirely opposite reaction including:
- dilating your pupils
- opening airways (this is why some recommend drinking coffee before exercising)
- your heart beats faster
- blood vessels constrict (this is why caffeine is in some pain relievers to reduce headaches)
- blood pressure rises
- blood flow to the stomach slows (perhaps reducing hunger)
- the liver leases sugar into the bloodstream for extra energy
- muscles tighten up, ready for action
What’s not to love? Recent research has even shown that adenosine receptor antagonists like caffeine can modify brain dysfunctions and diseases like Alzheimer’s disease, Parkinson’s disease, Huntingtons’s disease, epilepsy, pain/migraine, depression and schizophrenia.
When is the best time to drink coffee?
For most people, the hormone called cortisol is highest when you first wake up in the morning. Cortisol is a steroid hormone produced by the adrenal glands in your kidneys. It regulates a wide range of processes throughout the body, including helping to control blood sugar levels, influencing memory formation, influencing blood pressure, regulating metabolism and affecting immune response such as inflammation. It also plays an important role in helping the body respond to stress.
Because cortisol levels are strongly related to your level of alertness, some scientists are recommended that you should drink your morning coffee only once your natural morning cortisol-high has started to drop. For most of us who work a 9-5 job and get regular sleep, our cortisol levels peak, on average, between 8 and 9am. If you’re getting enough sleep at night, you shouldn’t need a strong cup of coffee or tea to get you going in the morning. Instead, you should be able to ride the wave of cortisol through to mid-morning.
Additionally, if you are drinking your morning coffee at a time of day when your cortisol concentration is at its peak, you’re already at your naturally highest level of alertness, so you can develop a tolerance to the caffeine (and end up spending twice as much money as you need to at Starbucks.
Instead, it is suggested that you drink your first cup of coffee between 9:30 and 11:30 am, when your cortisol levels are dropping. Try drinking water and getting some sunlight first thing in the morning. Even driving to work without wearing sunglasses can help you enjoy the stimulation from natural sunlight that will help wake you up. When you get settled in the office and have read through your emails, then get up and make that first cup of coffee. You’ll reap greater effects with less caffeine.
Too much of a good thing. How much coffee is too much?
According to Zagat’s annual coffee study, the average American drinks 2.1 coffee drinks per day and it increases with age. Harvard School of Public Health finds that 54% of Americans over age 18 drink coffee everyday. We’ve already discussed the benefits of drinking coffee, but there are several downsides:
- Jitteriness, nervousness and irritability. Caffeine can also make anxiety worse. Some people are more sensitive to these effects that others.
- Insomnia. because caffeine is a stimulant and blocks the sleep inducing effects of adenosine (see above) excessive intake or consuming caffeine too close to bed time can cause insomnia. Many specialists advise not to drink caffeinated beverages after 2pm to avoid this.
- Digestive issues. In large doses, caffeine can worsen diarrhea and symptoms of irritable bowel syndrome.
- Birth outcomes. Studies have shown that pregnant women who consume high amounts of caffeine may increase risk of late miscarriages and still birth.
- More calories. People who drink coffee regularly often add sweeteners and cream which are high in calories.
Are there other reasons why you’re drinking so much coffee?
If you’re drinking coffee throughout the day because you’re exhausted, you may want to talk to your doctor. Even though you’re spending enough time in bed, you may not be getting quality sleep. There could be an underlying issue, such as sleep apnea, that is causing your excessive daytime sleepiness. To learn more about sleep disorders, like sleep apnea, check out our educational resources, talk to your doctor, or request a consultation with one of our sleep specialists.
Fuentes:
http://www.yourhormones.info/Hormones/Cortisol.aspx
http://neurosciencedc.blogspot.com/2013/10/the-best-time-for-your-coffee.html
http://science.howstuffworks.com/caffeine4.htm
http://www.huffingtonpost.com/2015/02/27/how-much-coffee-per-day_n_6763422.html
https://www.hsph.harvard.edu/news/multimedia-article/benefits/
http://www.webmd.com/vitamins-supplements/ingredientmono-980-coffee.aspx?activeingredientid=980
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