Most people who go on adventure holidays feel new aches or pains with the extra exercise.
Getting fit before you go is important, whether skiing, walking, horse riding or cycling so that you can enjoy your trip.
There has been no research done that has shown a higher risk of joint pain just because the person is at high altitude.
The knee joints and leg muscles are usually the problem areas! Support bandages or braces can be useful. However, it is best to try and improve your muscle strength so that supports are not needed.
Using two trekking poles when walking can reduce the load on the knee joints, especially if there are lots of down-hills where the strain on the knees is greatest. This could be helpful if you already have a joint problem. Reducing your weight (if you are overweight) or that of your backpack helps.
If your joints or muscles start to hurt, slow down, lighten the load, and / or consider a rest day.
If you normally have joint pains, make sure you take your regular painkillers with you.
The temperature can be colder - make sure you have enough layers to stay warm.
Get fit with any form of exercise that is practical and increases your heart-rate.
Try and include at least a full day's suitable exercise each week for the month prior to departure.
If you are going to use trekking poles, get used to them before you leave.
After 6 hours riding on the first day, my knees were killing me. I knew I should have ridden more than 3 times before we went. I suffered over the next few days!