Fitness and thing involved with fitness need help plz?

Question

ok am a 18 year old male who goes to the gym and eat well most of the time the thing is I help with the not fitness the question am asking is I go for a bike ride I don’t go tried or puffed out I can ride up a hill fast but am legs get so tried so is there a way I can fix this?

Answer 1

Assuming you aren't riding a single speed or fixed gear bike, you need to change gears (to an "easier" one) and increase your cadence (pedal faster).  

I'm guessing you stand up and pedal as hard as you can to go up a hill faster.  DON'T!!  

As you are beginning the climb, dial back 1 gear (the chain should move inward, toward the bike, whether it's the front or rear derailleur).  This will make it easier to pedal.  Keep a steady cadence (cadence is the speed at which you pedal) and continue up the hill without standing.  As pedalling becomes more difficult, change down by another gear, but continue the cadence.  Stand and pedal hard/fast from about 70 yards below the peak of the hill, and finally, at the top of the hill, click "up" a gear or 2.  At the top it will be harder to pedal, but you'll go faster over the peak of the hill and increase speed on the flat or downhill and continue to gear up at the same cadence over and down the hill. This technique will save your legs, and is much more effective for climbing long hills or multiple hills.

It takes some practice to do this smoothly, but keep riding and you'll get it.