El Gato27

I use the stationary bike at the work gym and after 30 minutes I am drenched and I feel like I got a good work out.

Sometimes I ride (actual riding) for an hour and a half and barely break a sweat and feel fairly fresh.

Is it because I'm not coasting on the exercise bike or the wind isn't drying me out? If feels like I burn more calories in 30 minutes on the exercise bike vs 90 minutes of actual riding. That doesn't seem right.
Does anyone else have this experience?

Thanks.

WAID

Lack of wind and coasting are both major factors. I put a big box fan in from of my bike trainer and it feels much more like actual riding.

Marcus_Ti

You're drenched on the exercise bike, because you hit a limit as to how much you can cool yourself indoors before your body says "I'm overheating lower your pace". On a real bike, you have a ton of airflow that cools you off letting you work harder....at least, so long as it isn't dangerously hot and humid out.

Without seeing cadence data, there's no telling if you're a pedal-coast-pedal-coast sort or not. Similarly, without data there's no knowing how hard or not you're riding on a real bike--or not.

Doge

You could weigh before and after ride and see what you sweat off. Fact is when you are cooler, you sweat less. On the bike, you also cannot just look at HR, or any one thing. As you heat up, or riding in very hot conditions you HR will increase as well.

You can likely tell more by how you feel the next day. I've posted this many times, but start taking morning resting HR in bed before you get up. A real hard workout will elevate it the next day. I'm not saying you should do that, but it is a very good indicator of what your body thinks you did (or you are sick, or not sleeping).

caloso

DrIsotope

QFT. Moving briskly for 4 hours in December requires less water than a Z2 ride in July. I haven't had to put two bottles on a bike in months.

When I was stuck doing Zwift, I used a 600cfm centrifugal blower as a fan, and would still sweat buckets. Might drink two water bottles an hour.

That's probably a big part of why I hate the trainer.

canklecat

Different workouts.

On the trainer I work on spinning faster than I normally would on the road, mostly using an easier gear and sitting more heavily in the saddle. And standing to pedal to exhaustion -- which I wouldn't do on the road. I'd stop before my legs were shaking. And it's continuous pedaling.

On the road I'm working on more consistency while pedaling seated, and on some rough pavement, striated concrete and chipseal, there's a continuous low level effort just to stay in place on the saddle. Rough roads usually demand a harder gear and more downward foot pressure to stay balanced, so the same type of spinning I do on the trainer isn't practical on the road. And there's quite a bit of coasting, mostly in short bursts over rough patches -- with neck, back and shoulder injuries I take it pretty easy and support my weight on my legs while crossing rough stuff.

No matter how much I sweat on the trainer I've never felt close to dehydration and seldom finish a full water bottle even on a 90 minute or longer session. Riding outdoors in summer in Texas it's easy to get dehydrated -- probably true of many places where the temp is at least 90F. I've gone through three large water bottles in a 50 mile ride and still needed more.

But I've had some exhausting indoor sessions, especially doing intervals or extended standing while pedaling workouts. I avoid riding to exhaustion outdoors. I'm just cautious about taking unnecessary chances on the road. I want to be sure I'm alert and have enough left in the tank to avoid errant vehicles, etc.

Machka 

Yes.

These days, I can be sitting with a fan blowing on me, and be in a pool of sweat.

dabac

There's really no telling.
Exercise bike is a more "clinical" riding. I find it easier to do strict interval sessions on trainers. There's nothing distracting you from putting the power down.
Regular riding, I sometimes get caught up in the moment, and more like cruise for awhile.
Or I end up riding my heart out to hang with the group.

Jno

jpescatore

Agree with all previous points about sweating not being a good indicator but also: climbing long hills is about the only way I can get a workout cycling. outdoors that is equivalent to workouts on indoor trainers with power meter/control. Outdoor cycling there (at least where I ride) there are always cars, intersections, turns, etc - very rare to be able to push high power for extended minutes other than climbing. But, I think climbing outdoors is a way better leg workout for me than equivalent minutes on an indoor trainer.

Troul 

Dry heat vrs high humidity will mask the amount of water expelled.

Skipjacks

There is a mental aspect of this as well.

Riding outdoors with fresh air and scenery and enjoying the world around you is mentally healthier than being in a stinky gym with recirculated air and staring at someone who has no business wearing skin tight clothes.

Physically....my stationary bike wears me out much faster than actual biking does. I figure it's because I keep a nice steady pace on the stationary bike and can focus on the pedaling without worrying about being run over by a car or having to stop at the lights. But mentally....the real bike outdoors is much MUCH better for me.

burnthesheep

livedarklions

As a practical matter, I can definitely work out harder per hour in a gym, but I can't tolerate anywhere as many hours as I can on a bicycle. There's just a limit to the amount of gym time I can do before boredom makes it impossible to go further.

By the way, I rode about 70 miles with temps in the 30s a few weeks ago. I didn't even touch my water bottle for the first 40 miles and I was riding pretty fast. I agree with all of the other posters who say that sweat is really not a good measure of effort.

HerrKaLeun

The better workout is the one i enjoy more. So actual riding always wins. Maybe you need to spend twice the time outside to equal the calories burned on a trainer, but i rather enjoy 1 hour than hating a half hour.

canklecat

Thirst isn't a reliable indicator of workout effort either. I have to remind myself to drink in cool or cold weather. Every time I've had to pull over with abdominal muscle cramps it was on cool days when I wasn't thirsty and didn't drink enough. And I still use electrolytes in the water bottle in cool/cold weather. Seems to help fend off overall fatigue.

But on cool/cold days when I plan to ride only a hour at most, I'll drink before and after the ride, but may not even carry a full water bottle. Depends on whether I'm planning to tackle some hill climb PRs and want to save weight. So far, so good, but I wouldn't count on getting away with that on longer or harder rides in cold weather.

Carverbiker

Carverbiker

josephnsmith

Actual bike any day!

Milton Keynes

I totally agree. This winter I've had a hard time getting myself out of bed in the morning in order to sit and spin the pedals on the trainer inside during cold weather. However, when it's nice out and I can actually get out and ride, I often look forward to it. In fact, I'm really missing warmer weather so I can actually get out and ride every morning again. Just sitting in one spot and spinning pedals seems so tedious, even when I'm listening to something on my phone which keeps my mind occupied.

u235

This is me too. I tried my trainer a few times and just can't do it. In my mind bikes are to be used outside. I understand that many people can do it and take it to higher levels with Zwift and have their reasons and more power to them. I'm happy not doing it and no desire to figure out what it would take to be able to. I do a routine inside though and mix things up to make it tolerable like use an Elliptical, weights, punching bag, body weight things, kettlebells etc inside as a supplement when I can't ride outside for whatever reason. These may or may not be directly related to making me a better bike rider but that is not really my primary goal.

That being said and to get back to the OP question..
I use HR as my gauge of effort, not sweat. My inside cardio workouts are exclusive to an elliptical and are usually much more controlled, intense, and steady state. I rarely do intervals on purpose, I get enough of "interval" work doing other things. I average about 158 (90% my theoretical max) over the entire workout of about 45 minutes including warmup and cooldown and have at least 25 minutes straight above 95% theoretical max. My typical bike ride is about 130-145 for about 140 minutes and a lot of swings depending on wind, amount of red lights, temperature etc (there is my intervals). I could workout slower and longer inside or possibly more intense and shorter outside on the bike but it is what it is. It is up to me (or you) on the level you want to put into it. Inside workouts are not naturally harder but you can control the intensity easier.

base2 

In my experience, indoor trainers are a better work out for time spent, but not better than cycling outdoors. I figure it has to do with consistancy of time spent at power output X. Indoors vs outdoors I still expend around 450 calories in 30 minutes. My power output is still 200-220 weighted average. My average heart rate is still 150 bpm. The difference being is outdoors theres periods of 650-700 watts on a short climb, periods of 4-500 watts on acceleration, periods of 300-350 for longer 2-3 percent grades & all that is balanced by "active recovery."

On the trainer, all those neuromuscular aspects get stripped out. It's just one long drone of an effort. I've always suspected that long moderately stressful efforts on the trainer are better at forcing mitochondrial adaption due to time spent at effort. The pay off is consistency of speed and cardiovascular capacity on the road. On-road efforts are better at forcing muscle growth due to lesser time at much higher intensity. Like a a body builder going high weight/few reps. The benefit being raw power and ability to sprint.

Doing both is a well rounded approach. On paper both come out the same; In real life, both train different aspects of your physiology.

I am open to thoughts by others on this. Afterall my sample size is 1.

caloso

That's my experience as well. If I'm going to do an interval set, I need to ride out to an appropriate stretch of road that's uninterrupted, low traffic, and decently paved. I've got a couple of those spots, but they're all a fair ride from my house. And if there's weather, there's the extra time and hassle of more clothing and needing to clean my bike. But with the bike on the trainer, I can put on whatever old bibs and shoes, warm up, do the set, cool down, and hop in the shower.

Ironfish653

I'm not crazy about trainers, although I really want to get a set of rollers to work on my form. I live where it's really flat, so the only way I can train for hills is on a trainer or stationary bike. Typically I use the ones at my gym since SWMBO won't let me put a bike in front of the TV. (living room rug and what have you)

It's got hoods and 'shift buttons' and I've done the measurements to get it close enough to where my road bikes are. The most I've been able to do though, is a little over an hour. It's just that the lack of engagement, and that eventually you can't ignore the walls any more.

The main disadvantage of a trainer, that it's fixed to the floor and doesn't move, is also an advantage if you're doing really intense intervals (to 'failure') You can throw everything in to that last set, even if you're to flagged to keep a bike upright. (also don't have to deal with traffic)