When you first arrive at altitude you may feel a bit off, tiredness, headaches, disrupted sleep, lack of appetite and slight shortness of breath on exertion, these are all normal symptoms of your body adjusting.
The most important way to adjust is to listen to your body, don’t push yourself hard in the first days and if you feel short of breath, stop and rest. Keeping a good intake of food is also important even if you don’t feel like eating anything, although don’t overeat! You need to keep drinking, more than you normally would as your body needs more water at altitude. Around 2-3L per day should be enough, up to 4L if you are exercising a lot.
It is important to communicate with your guiding staff about how you are feeling, as they are well trained in judging as to what you are going through is normal adjustment. Don’t wait until you are feeling very unwell to say something, and listen to their advice about what to do!
All of the above signs are normal, however if they are extreme or continue after the first few days this could indicate you are not adjusting well.
There is no evidence to indicate that age, fitness or gender have any impact on how you will adjust, every person is different and the only way to know is to go to altitude and see how you feel, but of course keep in mind as this is an active trip fitness will help you with the biking aspect.
There are drugs that can be taken before arriving at altitude that may help with adjustment; again this is an individual thing to be discussed with you GP.