Caffeine & Dry Eyes

Whether or not you love a good cup of coffee or tea, there is often a healthy debate on the pros and cons of caffeine. Some testimony suggests that caffeine actually causes dry eyes due to its diuretic or dehydrating effect.

Current recent research suggests that coffee in moderation does not cause dehydration and is in fact merely an urban myth.

Too much caffeine and you can feel jittery, anxious, nauseous or find it hard to sleep.  High amounts of caffeine increase levels of a hormone called cortisol, commonly called the ‘fight-or-flight’ hormone.

Cortisol is released naturally by the adrenal glands and also acts as a stimulant. Cortisol is naturally highest in the mornings and at its lowest late at night before sleep. ( Well it should be )

Caffeine, Exercise & Testosterone

Studies on fitness professionals and athletes have uncovered that caffeine before exercise can demonstrate a number of unique and interesting benefits.
Exercise on its own, typically resistance training, has the ability to increase testosterone by as much as 15 percent, along with boosting other feel-good hormones like serotonin and dopamine.


Simply put, we feel better after that run, workout, or spin class! 

All the above mentioned hormones have positive effects on our brain and cognitive functions, along with influencing muscle development and repair.

Anecdotal reports from dry eye sufferers suggest that exercise helps and symptoms often feel less severe when getting regular exercise

Caffeine also stimulates the central nervous system and delays fatigue which is why we feel more alert after a morning espresso or caffeine drink.

Let’s be honest, this is one of the main reasons we drink caffeinated beverages; to get the day started, feel alert and ready to go.

While exercise is shown to boost testosterone levels, caffeine consumption at 200, 400 and 800 milligrams prior to exercise produced significantly larger increases in testosterone than exercise alone according to research.

A peak dose of 800 mgs provided a hefty 39% increase in testosterone after one hour’s intense exercise.

Note that 400 mgs a day is generally well tolerated by healthy individuals and approximates 2-3, 8oz cups of coffee (drip) or 4-6 shots of espresso.

Caffeine consumption also has a thermogenic effect that increases metabolism, body temperature and fat oxidation.


Caffeine and Dry Eyes. Is There A Connection?

Believe it or not, there just may be a connection between caffeine and dry eyes.
A Japanese study compared caffeine consumers to non caffeine consumers. The result was that tear film volume increased by 30% in the caffeine group versus a placebo. Participants in the study were healthy an did not have dry eye syndrome. 

How long the  tear film level remained elevated for was not determined but the result showed that caffeine consumption had a positive effect on tear film health.

Interestingly, consumption was based on participant weight. Within the range of 91 to 205 pounds, ( 41- 93 kilograms ) amounts of 300-500 mgs of caffeine were ingested in one dose.

The study highlighted that specific genetic markers in some participants meant that they were able to metabolize caffeine more efficiently and therefore saw larger increases in tear volumes. This suggests that not all caffeine users see similar results and that genetic blueprint plays a role.

Clearly caffeine intake in varying amounts shows a unique ability to increase hormone levels in our body, specifically testosterone.


Does Testosterone Help Dry Eyes?

Yes it does. We know studies show that healthy testosterone is critical to the health of our eyes. The meibomian and lacrimal glands need healthy testosterone levels to maintain regulation of the tear film itself and general function of the glands.

It could well be that regular caffeine intake aids the dry eye sufferer due its secondary ability to elevate testosterone levels and hence increase tear film health and keep the glands used in tear film production free from disease.

It appears that there is a link between caffeine and dry eyes. However, rather than creating a dehydrating effect that you might assume could potentially be a cause of dry eyes, caffeine can be beneficial in promoting healthy tear film along with providing a natural boost in testosterone.



Caffeine enhances testosterone during exercise  Beaven, Hopkins, Hansen, Wood, Cronin, Lowe. IJSNEM, Vol. 18, Iss. 2, April 2008
Bottomline Publications -Natural Solution to dry eyes
Caffeine increases tear volume depending on polymorphisms within the adenosine A2a receptor gene and cytochrome P450 1A2.

Arita RYanagi YHonda NMaeda SMaeda KKuchiba AYamaguchi TYanagihara YSuzuki HAmano S. SourceDepartment of Ophthalmology, University of Tokyo School of Medicine, Tokyo, Japan.

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