How Often to Do HIIT Workouts On and Off the Bike

Most fitness enthusiasts have heard of high-intensity interval training (HIIT). But how often are you doing HIIT workouts on (or off) the bike?

There’s a fine line between pushing your intensity enough to see results, and not too much that it leads to overtraining. So consider this your guide to make sure you’re not overdoing it on intensity—and that the HIIT work you are conquering actually pays off.

We spoke to HIIT researchers and cycling coaches to find out the best blend of interval workouts to boost your cycling fitness. The answers might surprise you.

We know that HIIT training improves your maximal oxygen uptake (or VO2 max), aerobic endurance, anaerobic capacity, and metabolic health. But what is it, exactly?

At the basic level, HIIT refers to working through periods of high-effort training (think 8 or 9 out of 10 rate of perceived exertion), followed by periods of rest, and repeated for a few rounds.

But HIIT is tricky because, as Paul Laursen, Ph.D., co-founder of HIIT Science points out, there are so many different workouts that people refer to as HIIT. Bootcamp-style workout classes like CrossFit, Orangetheory and Barry’s Bootcamp sort of fall into the HIIT category because they combine sprint-style efforts that boost your heart rate with strength training. But a set of sprints or threshold intervals on the bike also count as HIIT.

“HIIT is actually defined as exercise that is done in your red zone, which is above your threshold or critical power,” says Laursen. “It’s above that sustainable exercise intensity, so it’s unsustainable. That’s why the intervals need to be separated by rests.”

“The biggest misconception people have about HIIT workouts is that they have to be ‘no pain, no gain,’” says Laursen. “Get that out of your head. That’s never what coaches intended it to be. HIIT is just a training session that allows you to do more high-intensity work and is a potent stimulus. It’s not supposed to leave you a puddle on the floor; you should be able to walk away after a session.”

He also adds that HIIT workouts don’t need to be a grind. “It can be fun,” he says (and studies back him up on this). “It actually shouldn’t feel so hard or painful—you want to want to come back to it!”

Sunday is a race on Zwift. Monday is CrossFit. Tuesday is the group ride that always turns into a race. Wednesday is your interval workout. Thursday is an easy ride with some gym work. Friday is CrossFit, again. Saturday is your long ride. You should spot a problem here.

Overdoing HIIT—especially when you do these workouts both on and off the bike—is a common issue that keeps cyclists from making gains in their training or at the gym, says Laursen.

When you do too many HIIT workouts, even as you put in more effort, you’ll find yourself struggling to keep up, and finish workouts feeling exhausted and sore. Your body is probably begging for some recovery. HIIT is good, but too much HIIT can have the opposite effect on performance improvement.

As with most things in training, the answer to how often you should do HIIT workouts per week is going to depend on the individual, their goals on the bike, the part of their season that they’re in, and where in the training calendar they are. A cyclist who’s preparing for cyclocross season may do three hard interval sessions each week for three weeks, then take a rest week with only one shortened session. Then, during cyclocross season, that same rider may do no specific HIIT sessions or one shorter session during the week because he’s racing back-to-back on weekends for eight weeks straight.

In general though, Thomas says that two to three HIIT sessions per week tends to be the sweet spot during training periods. That includes group rides with harder riding, races, on-bike HIIT sessions, and off-bike HIIT workouts like CrossFit. More than three sessions per week tends to become difficult to recover from, and doesn’t allow for the equally important longer endurance-paced rides.

Typically, one interval session during the week should target shorter, harder efforts (VO2 max and above) for short durations, says Laursen. “These short intervals can be programmed with longer pause periods to dampen the lactate response, which is less stressful on the body,” he says. “I like these sessions because you can actually hit your target, walk away, and feel fine the next day.” An example would be a warmup, then 30 repetitions of 30 seconds at a hard effort with 60 seconds of recovery, followed by a cooldown.

The other longer HIIT session would typically focus more on threshold and just slightly above threshold efforts, like a warmup followed by two sets of 15 minutes at threshold with four minutes of rest in between, with a cooldown after.

Most recreational/amateur cyclists manage to ride five days a week, says Thomas. When he’s programming, he tries to use two or three of those days as HIIT sessions, varying the type and duration. “I usually program Mondays and Fridays as days off, and then a middle of the week HIIT session, plus a Saturday or Sunday group ride that tends to be on the harder side,” he says. “That tends to work well for most people.”

It’s important to note that advanced riders shouldn’t necessarily do more HIIT sessions. Instead, Thomas notes that the sessions may get longer—perhaps doing two sets of 20 minutes at threshold instead of 15 minutes, or doing three sets of 15 minutes at threshold instead of two. Or you can simply work harder in those intervals, raising power. For instance, a cyclist just starting out may do a 15-minute interval at 125 watts, but two years later, may be doing the same 15 minute interval at 250 watts. They’re not adding more sessions, the quality is just improving.

Most coaches will avoid scheduling back-to-back HIIT workouts because your body simply won’t be able to recover and absorb the effort. And that includes different types of interval workouts, like a hard session on the bike on Monday and a metabolic conditioning-type gym workout on Tuesday. While the movements are different, the effort is similar.

Of course, there are exceptions: During cyclocross season, for example, most racers will race on Saturday and Sunday, so there’s no avoiding two high-intensity workouts. But that means recovery during the week becomes even more important.

You definitely don’t need to do off-bike HIIT workouts, like a CrossFit class or bootcamp session, if you aren’t interested. In fact, Laursen recommends you don’t.

“You have to ask yourself: What are your goals? If you’re a cyclist and you want to do well in cycling, you should focus on specific training that enhances your cycling performance,” says Laursen. “That means doing HIIT on the bike if your bike performance matters the most. Your strength training should be specific and coordinated with your on-bike training.”

But if you love your CrossFit community and find that it motivates you and makes you feel great, it could have a place in your schedule—just make sure you’re not putting HIIT bike sessions right next to CrossFit classes. “If we start doing CrossFit-type classes alongside the HIIT cycling training work, you’re adding two stressors, which can be too much for some people,” he adds. “This can really beat us down, so you need to be careful.”

“I like to instruct people to actually be quite controlled during their intervals,” says Thomas. (So ignore those “pain cave” selfies that you see on Instagram.) “If you look at a classic VO2 max session—that’s four sets of five minutes at that hard effort—you really shouldn’t be emptying the tank or going all-out until the last effort. For the first three, you want to hold back a little bit. The last one, you can empty the tank. But if you empty the tank in the first one, you’re not going to be able to finish the workout very well.”

Aim for consistency over the higher numbers, he adds. The goal in a HIIT session is to be able to repeat the effort for the duration of the session, not wilt after the first rep.

Simply put, you’re doing enough HIIT if you’re seeing gains in your cycling and you feel recovered when you’re starting your workouts. Of course, it’s normal to feel a little tired sometimes—something Thomas knows very well since he’s currently training with a newborn in the house. But if you’re starting every HIIT session feeling exhausted, you’re doing too much.

“The majority of your training should be designed to be boring,” says Thomas. “That means most of it should be in zone 2—your endurance pace—and two or three sessions a week should have those harder efforts.”

Rather than play with adding more HIIT workouts, focus on doing those two to three workouts well. Think quality, not quantity.

If you’re easily hitting your power numbers in those workouts consistently, you may also want to consider re-testing your FTP to reset your zones: Remember, as you get stronger on the bike, your power zones will change! (Don’t do this more than once every few weeks, though, Thomas says.)

“If it’s taking away from your ability to execute cycling training, then you’re probably doing it wrong,” Thomas says bluntly. If you find that you’re not getting any better on the bike despite your HIIT efforts, that’s a sign to back off and give your body a break.

You can also look at your HRV—your heart rate variability—which is tracked by many of the current wearables, from Garmin watches to Oura rings to WHOOP straps. There are plenty of apps that track your HRV and offer suggestions around rest when your HRV is very low compared to your personal average.

You can also simply ask yourself how you’re feeling in the morning. “Another sign is if you’re not sleeping well,” says Thomas. “That’s a sign that something is causing a disruption.”

We’ll come back to what Laursen and Thomas have said several times here: Most cyclists don’t need to add more HIIT, they should simply improve the quality of their workouts.

Instead of adding more sessions, increase your power or increase the duration of your current intervals by adding another repetition or extending the time slightly. The goal isn’t to be the cyclist who’s doing the most work, it’s to be the cyclist who’s making the biggest gains in their training.

Bootcamp-style classes that feature lots of hard efforts and sprints are HIIT workouts, but a circuit of heavy weights at the gym is definitely not the same thing.

Unfortunately, Laursen points out, a lot of athletes equate a CrossFit-style workout with strength training, even though the two are distinctly different. In CrossFit—and most bootcamp classes—strength is done with a cardio component, so as you’re lifting, doing push-ups or pull-ups, you’re also doing heart rate-spiking movements like sprints, jumping jacks, or pedaling on an Aerodyne machine. In strength training, you’re doing slow, controlled movements that target specific muscle groups, and while you might breath hard after a few repetitions, you’re not spending 20 minutes in the red zone.

Laursen notes that cyclists might find significant benefit from strength training (the traditional way, rather than with that cardio component).

“I think there are some very specific movements that we can do to enhance our cycling performance, and we should be strengthening any areas of weakness in our body,” says Laursen. “But strength training doesn’t need to be high intensity, it can just be strong, powerful movements. You don’t have to be exhausted from the overall effort for strength training to be effective.”

Technically, yes—racing counts as HIIT most of the time, assuming you’re putting in a series of hard efforts (like sprinting out of corners in a crit or jumping off your bike to run over barriers in cyclocross). However, Thomas cautions against relying on racing for your HIIT training, since the unstructured nature means you’re not specifically targeting certain zones and while you’ll see some progress at first, you’re likely to hit a plateau if all you do is race.

“I don’t think racing or hard group riding will take you as far as you want to go,” says Laursen. “Once a week is great, but your other sessions should be more specific and targeted.”

Thomas agrees, and says that often, he has to tell cyclists to dial back their racing and group ride efforts in order to make improvements. “Bunch riding is a high-intensity session, but those rides just have cyclists smashing it randomly, without any structure,” he says. “But structured high-intensity interval sessions are really important. You want to target specific physiology during a session, and racing or group riding doesn’t do that. It’s more random, so you’re not improving anything specifically.”

Probably not. Of course, there will be times where you can’t avoid being tired thanks to work and family life. But for the most part, HIIT is best done when you’re feeling fully rested. You can use your heart rate variability (which is now tracked by most fitness watches and wearables) to give you an objective look at how well you’re recovering.

“If your heart rate variability is low, that means you’re sympathetically stressed,” says Laursen. “Studies have shown that if you do training in that sympathetically stressed state, you can get through the session, but you don’t adapt from it.”

If you are feeling tired or your HRV monitoring app is telling you that you’re in the red, swap your HIIT session for an easy endurance ride, says Laursen. If by the next day, your HRV is still depressed, take a day off. If it goes back to normal, don’t try to cram in that HIIT session that you missed, just get back to your regular training schedule.

Molly Hurford

Contributing Writer

Molly writes about cycling, nutrition and training with an emphasis on bringing more women into sport. She's the author of nine books including the Shred Girls series and is the founder of Strong Girl Publishing. She co-hosts The Consummate Athlete Podcast and spends most of her free time biking and running on trails, occasionally joined by her mini-dachshund.