What Happens to Your Body When You Ride a Century

Peter Glassford
by Peter Glassford
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What Happens to Your Body When You Ride a Century

Completing a 100-mile ride — also known as a century — is a popular training and racing goal. Many consider it the cycling equivalent of running a marathon. The experience of riding 100 miles can push your body and mind to the limit. But what exactly happens to your mind and body when you head out for that 100-mile ride?


Mentally, these early portions of the ride, including getting out the door, can be tough and even professionals need help sometimes, so feel free to enlist a friend, even if they won’t do the full 100 miles with you. Rally pro cycling’s Ryan Anderson says, “Sometimes, I’ll ride with someone else to have company for the extra hours.”

As you head out on a century ride, you will have energy and feel strong mentally. This is both good and bad. Because it’s early, your perceived exertion (RPE) will be low in this first portion of the ride. Keep it that way. Payson McElveen, an experienced endurance racer, described his strategy in events as staying bored as long as he can. Follow his advice and stay in that ‘bored’ zone: Don’t get too excited, try not to breathe too heavily and keep your fuel and water flowing.

Riders who push too hard early in a long ride find they hit the wall as they burn through their easy-access fuel stores. The concept of critical power (or heart rate) helps to explain pacing: Many riders get excited early and produce peak power and heart rates in the first couple hours only to fade later in the ride.


When you start to get beyond the midway mark, you will probably begin to have mixed feelings. You are likely starting to feel the fatigue of the first 50 miles, but you are also over the hump and can start counting down the miles. Many riders will be intimidated by this feeling of being equally far from the start and the finish, so pay attention to your effort and be prepared to talk to yourself positively to motivate and ensure your brain you are experienced.

Anderson suggests another tactic you can use to get through your long rides, especially when you feel like the finish is a long way off. “I mentally break up the ride. The first two hours, just get through those. Then, you only have four to go,” he says. “Break it into manageable chunks.” For many riders, this might be taking the ride in 25-mile chunks or focusing more on your fueling and eating every 30 minutes versus dwelling on how many miles are left in the ride.

Fueling and hydration are incredibly important to stay on top of at this point. What you do in the first hour from a nutrition and food standpoint is not necessarily what you are going to be doing in the sixth hour. Stacy Sims, PhD, senior research scientist at the University of Waikato, says, “When we think about ultra-distances, your body is not static.”

“Your body is slowly dehydrating. Your gut is becoming a little bit more sensitive,” she explains. “You are not going to be able to digest food as quickly. You are going to have times when you are going to hit lulls. When you hit those lulls, you do not need to force food down.” Rather, Sims says, try to listen to your body — a lull where you’re not hungry may mean you haven’t been drinking enough for your body to digest the food you’re putting in, so take a few sips. Riders can also avoid this feeling by bringing a wider variety of flavors with them — a salty, savory snack might be much more appealing than another sugary gel at mile 65.

Your heart rate may very well be increasing despite a stable RPE and power at this point in the ride, especially if it is hot. Michael Hutchinson, author of “Faster,” describes how dehydration affects the cardiovascular system by making your heart pump less per beat as your blood volume drops and compensates with a higher heart rate to get the same output. Staying on top of hydration and cooling helps extend your endurance.


As you near the finish of any effort, your brain generally lets you ’empty the tank’ and charge just a little harder. Alex Hutchinson, author of “Endure,” suggests much of our performance as things get hard is limited by our expectations and how they compare to our current perceived exertion. It may be that preparing to feel tired and less motivated in the final hours of a century ride helps you endure.

In these final stages of the ride, your heart rate is less important and your RPE and perception of your position in the race or on the course become relative to what you have left in the tank.

Pro mountain biker Evan Guthrie says this is where mantras and self-talk come in, “I tell myself ‘One more lap’ until the race is done because I can always do one more lap.” For long events, try associating a distance with the ride you do on your commute to work or ride with your kids (if you have 10 miles left in your ride and your bike commute is 5 miles, remind yourself you ride that distance commuting every day or that you’ve ridden 10 miles feeling bad in training and you know you can gut out 10 more miles).

Remember, toward the end of the ride or race, it is OK and maybe even better to fade a bit. That means you’ve emptied the tank in those final miles. Don’t stress if your pace doesn’t stay perfectly steady throughout your ride.

Blood tests after long rides show increased immune system activation. So, again, fueling during your ride helps avoid going too deep into fatigue and stress response. A good post-ride snack soon after finishing and another meal a few hours later helps avoid too much immune response or prevents an illness that reduces the benefit you get from a long training ride and increases your recovery time.

When you’re finished, make sure you focus on steadily (and slowly) rehydrating. Even if you guzzle water along your ride, you’ll likely still be slightly under-hydrated, so keep an eye on the color of your pee. Try to get back to a light yellow color gradually over the next 24 hours. Include plenty of high-quality carbohydrates and protein in your recovery meal, especially if you relied on simple sugars for the entire day.

Last, take a minute to congratulate yourself and bask in your successful completion of 100 miles — it’s a great physical, mental and emotional accomplishment, and you should be proud!

About the Author

Peter Glassford
Peter Glassford

Peter is a cycling coach and registered kinesiologist from Ontario, Canada. He travels frequently to work with athletes at races, camps and clinics. He also races mountain bikes for Trek Canada and pursues adventure in all types of movement. Follow @peterglassford on Twitter, or check out his online and in-person coaching at www.smartathlete.ca.


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