Madelyn Fernstrom

7 things you didn't know about caffeine

Sep. 20, 2012 at 11:07 AM ET

Feeling groggy this morning? It's OK - reach for another cup of coffee. Here, we give you some surprising facts about caffeine.

1. Caffeine helps athletic performance. 

Scientific studies on athletes have be ongoing for more than 35 years. Caffeine is documented to boost athletic power and endurance, so you can exercise harder and longer. Caffeine has a direct metabolic effect on muscle, to improve endurance. In biological terms, caffeine helps muscle burn fat as the energy source, instead of glycogen (a carbohydrate). This difference in type of fuel boosts endurance.

To get a rough idea of effective “dose” for yourself, take your weight in pounds, divide it in half, and multiply by three.  So, if you weigh 200 pounds, that would be 100 x 3  = 300 mg.  That’s the amount in a large coffee. There are caffeine pills (like NoDoz), but stick with coffee. Also, too much is bad for performance. Studies also show that excess caffeine intake doesn’t give you a further athletic boost; instead, it decreases your performance.

2. Caffeine can boost mental focus and alertness.

Caffeine easily gets into the brain, and affects many kinds of neurons (brain cells) in a positive way. Studies continue to show that caffeine can increase mental focus and concentration. Caffeine is really “nature’s stimulant” – in caveman times, a quick boost when you had to run away from a predator trying to eat you, or needed extra energy to go forage for food. While moderate caffeine intake can boost your ability to concentrate, and improves mental alertness, it doesn’t make you smarter – and has no effect on learning! DOSE is important – and that’s what we look at in our next fact.

3. The less caffeine you consume, the better it works.

While body and brain receptors (sites of action) respond to caffeine as part of normal biology – the more you use, the more your body gets used to this signal, and stops responding the same way. The response is much less. This is call attenuation. Same dose of caffeine, less effect. With this knowledge, the best way to have optimal effect of caffeine is to limit consumption to about 300 mg per day, and consume it ONCE a day – at the time you want to be most alert, and want the maximal effect. For many people this is the morning. And, if you limit your total caffeine intake, when you need a quick pick-me-up at another time of day, you’ll still get it. For example, you have an evening meeting, and have a 10 oz. coffee around 5 pm – you’ll get a boost in energy and mental focus, IF you are a low consumer (one cup a day in the AM). So, save if for when you need it!!

Too much caffeine is a health negative, with symptoms like anxiety, sleep disturbances, digestive problems, muscle twitching, and heart palpitations. Caffeine is “natural” (part of nature), and like all things in nature, a little is a health-promoter, a lot is a health-negative.

4. Caffeine is not addictive.

There is no physical dependency of caffeine – and it doesn’t matter what source of caffeine is consumed (coffee, tea, cola). You might feel dependent on a certain food-source of caffeine, but it is not the caffeine alone.  There are no negative physical symptoms of “withdrawal”, except for a temporary headache, which typically lasts for several days. To avoid the “caffeine headache”, don’t go cold turkey, and cut back gradually. Make your coffee half-decaf, or alternate one regular cup, and one decaf cup. In fact, caffeine is often a treatment recommended for headache sufferers. While the mechanism of why caffeine is related to headaches, one theory is that it is related to caffeine’s effect on blood vessel “relaxation” (opening up a little more) in the brain.

5. Coffee has three times more caffeine per cup than tea or cola.

We’re in a big gray area here, as amounts in sodas are fairly standard, but a lot of variability occurs in coffee and teas. It depends on the roasting of the beans - the darker the roast, the LOWER the caffeine content, even though it tastes stronger. Different kinds of tea leaves contain differing amounts of caffeine, and brewing time alters the caffeine content. (Note – chocolate has very little caffeine, compared to other foods sources). Colas are more standardized, although there are some exceptions with soda, like Mountain Dew, with more.

That said, as a general rule – coffee has about 150 mg in a cup (medium mug) – with the same volume of tea containing around 50 mg, A 12 ounce can of soda is around 50-60 mg.  Be aware of servings – as this adds up fast. A general health rule is to limit daily consumption from all sources to about 300 mg per day. 

Important – food sources of caffeine – tea, coffee – also have value-added health benefits, unrelated to caffeine, occurring from antioxidants in tea leaves and coffee beans. There are also non-food sources of caffeine – including NoDoz (caffeine pills), some analgesics (complex headache over the counter meds), and asthma medicines (a related form of caffeine – so beware of caffeine intake when taking asthma medicines).

6. Caffeine sensitivity is inherited.

Caffeine has to be broken down in the body, and it's activity and actions depend on how long it hangs around, intact, before it is broken down and excreted (in the urine). This is a metabolic process, and this can have a genetic predisposition in families. This means that if your parents seem to get strong effects of caffeine on a small amount - a half cup, say - you are likely to have the same kind of response. Look to your family tree, to get a clue of how much caffeine might work for you in a health promoting way. This does vary!

7. Excessive caffeine can be lethal.

While this is extremely rare, too much caffeine can have cardiovascular effects that can cause death. Because caffeine impacts the nervous system, heart rate, and blood pressure, if you are susceptible, it can have severe effects. This is more likely with caffeine pills and high-caffeine energy drinks.

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