Thursday, April 7, 2016

Caffeine and Running

This post was originally featured on Salty Running.

Caffeine is everywhere these days. It comes in gum, gels, and jellybeans, and even in sprayable cans, powdered form, and, briefly (pun intended), in underwear. And certainly, for many, it comes in the form of a morning cup of joe.

Runners especially seem to cling to the caffeine. After all, training can be exhausting, often taking place in the wee hours of the morning or after a long day at work. We need a jolt to get out the door … and maybe a caffeinated gel to get through the final miles … and maybe another cup to revive us enough to tackle the rest of our jam-packed days ... and then maybe an afternoon latte to stagger through to 5:00.

But there’s a lot of talk about caffeine and whether it’s good or bad for us, especially as runners. Does it give us a boost or give us the trots? Does it dehydrate or replenish? If we drink that morning coffee day after day (along with the afternoon mug) will it still give our run a boost? Below is a summary of what we know about our daily cuppa.

Not exactly unbiased:
 Caffeine contributed to the writing of this post. 
The Good

Caffeine is a known performance enhancer, so much so that it used to be banned by WADA. Caffeine helps reduce perception of effort (it feels easier to nail a fast pace), increases muscle contraction, and ups the circulation of free fatty acids during high intensity workouts, sparing those precious carbohydrate stores. And of course, it perks us up during exhausting training weeks. Many of us couldn’t get through the daily grind without our morning grind. In fact, one reason it’s no longer banned is its ubiquity in our culture; 85% of Americans consume caffeine daily.

The Bad

Sadly, there’s bad news brewing too. If taken before or during exercise, caffeine can reduce blood flow to the heart. This is troubling because the heart is pumping harder during exercise, so it needs more blood, not less. Some speculate this may be a cause of sudden death in marathons, although no death has been specifically linked to caffeine yet. Based on the possibility, the International Marathon Medical Directors Association warns runners not to consume more than 200 total milligrams of caffeine before and during a race. Those most susceptible are people who don’t regularly consume caffeine, have heart disease, or take it in high doses (like those found in energy drinks). If you have heart trouble, please don’t use this post as a reason to start chugging energy drinks. Talk to your doctor first and be cognizant of the caffeine levels in your drinks and gels… and how quickly they can add up.

The (Could Be) Ugly: Bathroom Issues

This could fit in the good or bad categories, depending on your situation. Some runners love a cup of coffee before a run; it gets things moving so there’s no need for a bathroom stop later. Others find it works a little too well in that area and end up with the trots. If you’ve been experiencing bathroom issues on your runs lately, you might consider examining your caffeine consumption and see if adjusting it helps.

One oft-cited con of caffeine is that it makes you pee more often, potentially dehydrating you. Fortunately, this has been debunked in recent years; there appears to be no difference in fluid balance (i.e. urine volume) after drinking water or caffeinated beverages, particularly if you’re a regular caffeine user.

How Much?

To get a helpful performance boost, the recommendation from most studies is 3-6 milligrams per kilogram of body weight. For a 130-pound woman, that’s about 180-350 milligrams of caffeine, or around 12 ounces of strong coffee or three 8-ounce cups of tea. (Note: the high end of this is much more than the International Marathon Medical Directors Association recommends.) More than that doesn’t seem to provide any additional benefit.

Obviously, it’s important to know your body. If you have heart problems, are on certain medications, or are pregnant, you may need to limit your intake. Furthermore, people metabolize caffeine at different rates. A genetic test can tell you if you metabolize caffeine quickly (you get a jolt quickly, but it fades quickly too) or slowly (it takes longer to work, but lasts longer too). But based on your own experience, you probably already know this without knowing your genes. If caffeine takes a while to kick in, you might want to try drinking it an hour or so before the race, while if it hits you quickly, you might try taking a gel just before the start and supplement during.

Do You Need to Give it Up Before a Big Race to Get a Boost?

Some coffee addicts have success tapering caffeine leading up to the race. Since your body is habituated to its daily dose, lowering your tolerance may allow a cup of coffee or caffeinated gel to give you a bigger boost on race day. But some think it’s not worth the misery of withdrawal symptoms when you’re already cranky from tapering. The science is mixed; there seems to be no consensus whether your tolerance matters for performance benefits.

Anecdotal evidence is mixed too. I tried cutting back on tea (my main caffeine delivery system) before my last race, but didn’t sense much difference. But my friend Laura (aka Salty's Barley), an avid coffee girl, has had great success. If you want to try it, she recommends slowly easing off it starting one to two weeks before the race. To counter the withdrawal, she starts by drinking half-caf and then progresses to decaf.

My caffeine delivery system: A cup of tea for T. 
Coffee for Recovery: Is it the New Chocolate Milk?

Consuming carbohydrates along with some protein, like in chocolate milk, after a long workout is crucial to replenishing fuel stores and promoting recovery. But research also shows that combining caffeine with the carbs could give an additional boost. One study found that a post-workout combination of carbs and caffeine led to increased glycogen stores (the energy supply we use up during long runs) a few hours later compared to post-workout carbs alone. Another study found the combo may help runners bounce back after a long workout; people given both carbs and caffeine performed better on a sprinting test a few hours later. (Some caveats: both studies were small and used a LOT of caffeine, equivalent to about 5 cups of coffee.)

Though the research doesn’t seem as robust as for chocolate milk, it is comforting, especially when you're slamming a coffee post-run on the way to work. Who knew that was helping you recover?

In Summary

Overall, the studies provide some good news for coffee lovers to contemplate as they sip their morning mug. But for those new to caffeine, start slowly (perhaps with tea or a gel with 25 milligrams) and if you are at risk for heart trouble, consult your doctor first.


  1. Interesting post! This training cycle, I started having caffeine-related issues. I always have espresso before a long run or a hard workout and I usually have one or two caffeinated gels during a LR (20mg/25mg). While I never had issues during my hard workouts, I started feeling suddenly out of breath during my LR after taking a caffeinated gel. It rarely happened to me in the past, but honestly caffeine is the only reason I could think of because LR pace is not fast enpugh to feel out of breath. Now that you explained that caffeine can reduce blood flow to the heart, this makes even more sense. Probably having coffee before agrees with me because my body has enough time to process the caffeine while, if I have caffeine during a run, that gives my body to much work to do.
    I usually give up coffee a week before my marathon. I mostly do it to sleep better at night (I'm so nervous on marathon week!), but also for the extra boost of marathon day.
    Could I ask you what's your routine for a marathon? Do you usually have coffee+caffeinated gels/how many? THANKS!

    1. I actually don't like coffee and only drink tea, haha. (But I used a lot of coffee examples in the post since I know that's what most people prefer.) Before a marathon I usually have a big cup of black tea (~50 mg) and then a caffeinated gel right before the start. I take that gel purely for the caffeine boost (or the placebo effect!) since I clearly haven't run low on fuel yet... Then I take 2 more gels during the race. (The gels I use have 25 mg caffeine.) It definitely varies person to person though, so find what works for you! It might be that caffeinated gels just don't work for you, but coffee will give you a bigger boost to start with.

    2. THANK YOU! Def changes from person to person, you're right!

  2. I've always wondered if there's a recovery difference between regular milk and chocolate milk. Do people just like chocolate milk more so it's more popular?

    1. Great question, Carina! The reason to go with chocolate milk is the chocolate adds more carbs. Some research claims the ideal ratio of carbs:protein post workout is 4:1, but regular milk is closer to 1.5:1. Some experts say the 4:1 ratio is overblown though, so regular milk might be fine... but when chocolate milk is so delicious, why not go with it? ;-)

  3. This a great post and I wish there was more awareness about caffeine and distance running. After a recent diagnosis of heart issues, I cut all caffeine and it is amazing the difference in my daily rhythms of awake/asleep/midday lulls. I haven't been able to run so I haven't been able to test if it impacts my running but I don't intend to test that. I've ready some things from the American College of Cardiology in my quest for knowledge to supplement what my doctor has been able to explain, and suddenly I'm worried about all my marathon-running, red bull-chugging friends.

    1. Thanks for your insight! Yea, I think it's important for people to be aware how much they are consuming: those gels really add up!!