You sweat in the stomach (I guess you meant the skin covering your belly) and face?
Not your armpits, chest, neck, back...?
Sometimes it can take a couple of months for your cooling system to get up to par, while getting in shape.
Make sure you do not overheat. Sip water every few minutes and workout in cool temperatures or use a fan while wearing the proper exercise clothing. Nowadays, some revolutionary fabrics (like Coolmax or CoolBalance) take your sweat in but instead of absorbing it and looking wet (like cotton), it evaporates so you stay cool.
I think a stationary bike is the best exercise to lose body fat, because it’s a non-weight-bearing exercise (you’re sitting) so you can do it for a couple of hours. Also, you’re not biking outside and worrying about falls or who’s going to run you over. Even bikers in bike races or rides kill each others in collision when one falls in a bad way. My mother died instantly falling off a bike (she was not wearing a helmet. Helmets were not customary at the time). I only use a real bike in Holland.
Now, do not use the “highest setting” whatever that is on your bike (I would guess a higher setting would be like you’re going uphill?). My bike just has a timer, speed, distance and a bunch of other things related to calorie expenditure based on pulse, age and sex, which I don’t use because I use a heart rate monitor and know my average calorie expenditure/minute (8 calories...I’m 125lbs) and my THR zones (Target Heart Rate).
I use my heart rate monitor to stay in my Aerobic Zone (70-79% of your MHR – Maximum Heart Rate). About another answer you got...do not do spin classes unless you’re fit as those are more to improve cardiovascular fitness (speed, endurance...) not to burn body fat. At 80% of your MHR and above, you get up to the Anaerobic Threshold Zone...then your Aerobics become Anaerobics and fat burning shuts down as it’s too intense for your body to get enough oxygen to process fat cells (you don’t need oxygen to process sugars). And then you run out of energy faster once you deplete your blood sugar level so you need to stop and replenish (eat) to restore your blood sugar level (which is very important for your body as it’s your “instantly available” energy source in case on an emergency so you get hungry). Also spinning forces you to focus on intensity, so you cannot really “zone out” and watch TV or read...so it could get boring.
Use the lowest setting you can find or the lowest speed that you can bike while still staying in your Aerobic Zone. The lower the intensity, the higher the percentage of fat used.
Also your body needs about 20 minutes to start using a percentage of fat reserves for energy, so the longer you do it, the better.
After 20 minutes, you could burn 20/80% fat/carbs if you’re unfit or a 65/35% fat/carbs if you’re very fit in the Aerobic Zone. So the less fit you are, the more carbs you need (fit people have a better ability to process fat cells as they have more fat-burning enzymes).
Let’s say that I burn 50/50% fat/carbs as I’m neither unfit nor an athlete. I burn 32 calories per mile biking which is 400 calories/hour at a slow 12.5mph speed. I would burn 800 calories while zoning out and watching a movie or 2 hours TV or reading a magazine. Then my speed would start to go down, unless I would put more effort into it, so I know that I depleted my blood sugar level and need to cool down, stretch and replenish.
For the first 20 minutes, I would burn 160 calories of carbs, then 50/50% fat/carbs would be 320/320 so my total need for carbs would be 480 calories (I would need a good high carbs meal about 2 hours prior exercising, for energy, so I can exercise for 2 hours) and I would burn 320 calories of fat reserves.
The Heart Healthy Zone…50-59% MHR
The Temperate Zone…60-69 MHR
The Aerobic Zone…70-79% MHR
The Anaerobic Threshold Zone…80-89% MHR
The Redline Zone 90-100% MHR
My stationary bike is one with moving handles. I can operate it with my legs, or my arms or both, so I get an upper body workout as well.
Even then, I also do other aerobics to avoid boredom and challenge my body in different ways. I walk/jog and swim but neither of those activities burn a lot of body fat for me because I cannot do them for hours (they’re weight bearing exercises...you have to move your body forward).
Also incorporate weight training in your workout schedule. Not only extra added muscle mass will devour your body fat on a 24/7 basis, all year long, but will make you stronger (and toner, and thinner...) and will make your aerobics easier and more efficient.