Bike vs treadmill: what the studies measured for oxygen, heart rate, effort and peak tests

A treadmill and a stationary bike both raise your heart rate for as long as you keep going, and they ask for it in different ways: on the treadmill you walk or run in place, on the bike you sit and pedal. Several lab studies put the same people on both machines and measured oxygen, heart rate, energy and effort. This page covers what they found, what they didn't test, a calorie estimate for each, and how to choose or mix the two. Setting the machines up is on the treadmill workout and the stationary bike workout; running and cycling as activities, indoors or out, are on running vs cycling.

Bike vs treadmill at a glance

In one session: oxygen was higher on the treadmill, heart rate wasn't clearly different

• Matched stages, more oxygen on the treadmill. In Kwon 2025, 22 healthy adults (17 men and 5 women, average age about 27) did a treadmill session and a stationary bike session, each in three stages of rising intensity set by the talk test: speech comfortable, then possible but somewhat difficult, then very difficult. The treadmill started at a self-chosen comfortable walking speed and added incline every two minutes; the bike started at 30 watts and added 30 watts every two minutes. Across the three stages, oxygen use per kilogram was higher on the treadmill (between-machine P = 0.040), and METs and the respiratory exchange ratio also differed between the machines; for the other measures, heart rate, ventilation and rated effort among them, the paper reports no significant between-machine difference. The abstract says there were no differences between the machines, but the Results and Table 2 report three (METs, VO2/kg and the respiratory exchange ratio).¹ The authors say the small sample may have limited the statistical power,¹ so a result of "not significantly different" in 22 people isn't proof the two are the same.
• More energy at the same effort. At the same rated effort, the treadmill used the most energy, or tied for the most (with a ski simulator in the men of the second study, and with the ski simulator and the rower in its women), in all three studies that compared indoor machines (13, 19 and 30 adults), and the bikes sat below it in every one: the two bikes were the lowest of six machines in the first, the cycle ergometer was lowest with one other machine in the second, and the three bikes were among the bottom four of seven in the third.^2,3,4 People chose their own pace in those studies, the third used a hard rated effort plus a maximal bout, and the abstracts don't say who walked and who ran on the treadmill.
• The same heart rate when people picked the pace. In Hansen 2025, 21 healthy adults did 16 minutes on a treadmill and 16 on an indoor bike at an intensity they chose. Heart rate, as a share of each person's maximum, wasn't significantly different between the two. Enjoyment scored higher on the treadmill, and intensity was about 4 percentage points higher during the mode a person preferred.⁵
• Intervals: the bike felt harder. In Kriel 2018, 12 sedentary men, average age about 24, did a cycling interval session at their own pace on a bicycle ergometer and a running interval session at a set pace on a treadmill. The cycling session drew higher oxygen use, heart rate and rated effort, and the running session was rated more enjoyable.¹³ The two sessions weren't paced the same way, so this compares those two sessions, not the two machines in general.

Peak tests: runners scored higher on the treadmill, cyclists differed

• Runners scored higher on the treadmill in all three studies. In Fernhall 1990, 14 trained participants (7 runners and 7 cyclists) did graded exercise tests on both machines. Both groups reached lower peak oxygen uptake on the bike than on the treadmill: 50.1 against 59.6 mL/kg/min in the runners and 55.1 against 59.4 in the cyclists. The runners' peak heart rate was also reduced on the bike test.⁶ In Verstappen 1982, 16 competitive athletes (8 distance runners and 8 cycle racers) did maximal tests on both: the runners' oxygen uptake was about 14% higher on the treadmill, and the cycle racers worked more efficiently on the bike.⁷
• For cyclists the three studies differ. In Verstappen's cycle racers oxygen uptake was the same on the two machines, and in Fernhall's cyclists it was lower on the bike. In Marko 2022, 31 elite teenage athletes did a maximal test on a treadmill and on a bike: the runners scored about 7% higher peak oxygen uptake on the treadmill, and the cyclists about 8% higher on the bike.⁸ I won't pick a winner among them; the athletes, the protocols and the ages differ.

The practical reading is that a VO2 max number from one machine doesn't carry one-for-one to the other, and, since the runners in Fernhall 1990 had a reduced peak heart rate on the bike test, that a heart-rate number from one machine may not carry over to the other. How to improve VO2 max has the training trials, and the heart-rate zone calculator shows the zones many people train by.

Over weeks: no clear difference for fitness

Menges 2026 pooled 7 randomized trials, each at least four weeks long, that compared running-only training with cycling-only or mixed training in trained or recreationally active people. Between running-only and cycling-only training there were no statistically significant differences for VO2 max measured on a treadmill, VO2 max measured on a bike, or running time trials.⁹ Those trials compared running with cycling, not a treadmill with a bike specifically, and the authors caution that there are few studies, some with a high risk of bias, and the evidence doesn't show the two are interchangeable.⁹

Calories: an estimate, not a measurement of you

The Compendium of Physical Activities lists an energy cost, in METs, for more than a thousand activities. One MET is about 1.0 kcal per kilogram of body weight per hour.¹² It lists walking on a treadmill at 3.5 to 3.9 mph, level, at 4.8 METs and at 4.0 to 4.4 mph at 5.8;¹⁰ a stationary bike at 70 to 80 watts at 5.8 METs, 101 to 125 watts at 6.8 and 151 to 199 watts at 10.3;¹¹ and running at 6 to 6.3 mph at 9.3.¹⁴ For a 70 kg (about 154 lb) person, 30 minutes works out at about 170 kcal walking at 3.5 to 3.9 mph and about 200 at 4.0 to 4.4 mph; about 200 on the bike at 70 to 80 watts, about 240 at 101 to 125 watts and about 360 at 151 to 199; and about 325 running at 6 mph. These rows aren't matched for effort, since a speed and a wattage don't feel the same, so the numbers show how the estimate moves with the setting, not which machine "burns more". The Compendium's own authors say its values are a starting point and don't reflect precise energy use for any one person.¹² For your own weight and pace, the walking calorie calculator uses the same walking rows.

What these studies didn't test

The single-session studies were small and mostly in young or middle-aged adults; Marko 2022 tested elite teenage athletes only, and the peak-test studies used trained runners and cyclists. Kwon 2025 matched the machines by talk-test stage rather than by speed or watts, and its abstract doesn't say how trained its 22 adults were. The meta-analysis pooled seven trials of trained or recreationally active people, and its authors call the evidence uncertain. None of these studies followed anyone's body weight or body fat, and none measured pain or injury, so this page makes no claim about any of them.

How to choose, or mix them

As a practical guide, not a finding:

• You'd rather stand, walk or run: use the treadmill. The treadmill workout has walking, jogging and interval sessions.
• You'd rather sit, or want a long easy session: use the bike. The stationary bike workout has a steady ride and an interval ride.
• Training for an event: do most of it on the machine that matches the event. The peak tests above followed the athletes' training.^6,7,8
• Mixing: one of each a week is fine. Count both toward the World Health Organization's 150 to 300 moderate minutes a week, or 75 to 150 vigorous.¹⁵ How to build endurance shows how easy and hard sessions fit together.
• Lifting too: Cardio and lifting covers the order and spacing.

If you have pain, an injury or a medical condition, stop and ask a doctor or a physical therapist. I'm a fitness coach, not a doctor.

Common questions

Is a bike or a treadmill better for cardio?

Over weeks of training, the 2026 meta-analysis of 7 trials found no statistically significant difference between running-only and cycling-only training for VO2 max or running time trials.⁹ In a single session, oxygen use per kilogram was higher on the treadmill at matched talk-test stages,¹ and the treadmill used more energy than the bikes at the same rated effort.^2,3,4 Both are cardio.

Does a treadmill burn more calories than a bike?

At the same rated effort, the treadmill used more energy than the bikes in all three lab studies that compared machines, though they don't say who walked and who ran on it.^2,3,4 By the Compendium's estimate it depends on the speed and the watts: about 170 kcal for 30 minutes of treadmill walking at 3.5 to 3.9 mph against about 240 on a stationary bike at 101 to 125 watts, at 70 kg, and more than that run for a ride above 150 watts.^10,11,12

Bike or treadmill for weight loss?

None of the studies on this page followed anyone's body weight or fat, so this page makes no weight-loss or fat-loss claim for either machine. How to lose body fat covers what matters most, and cardio vs weights for fat loss has the trials that measured body fat over weeks.

Is my heart rate the same on a bike and a treadmill?

Not necessarily. At matched talk-test stages in 22 adults, and at a self-chosen pace in 21, heart rate wasn't significantly different between the machines.^1,5 At the peak of a graded test, the runners in Fernhall 1990 had a reduced peak heart rate on the bike test.⁶ If you train by zones, check the number on each machine against how the effort feels.

If you'd rather have the week planned

Bike or treadmill is a small decision next to fitting either one around lifting, work and the rest of your life. Coaching is the version where your workouts are built around the days you actually have, and a weekly call looks at the week you just had and rebuilds the next one around what's coming. Coaching for a week that doesn't hold still explains how that works, and apply is the first step. Otherwise: ride 20 easy minutes once this week and walk or jog on the treadmill once, and keep the one you looked forward to.