As with many conditions, the root cause is posture. the neck and spine have a natural posture we're meant to use most of the time. Competitive road cyclists' p

As with many conditions, the root cause is posture. the neck and spine have a natural posture we're meant to use most of the time. Competitive road cyclists' posture is completely forwards, for aerodynamics, better climbing, etc. Using it may be a useful tool in your 20s / in competition but otherwise it is wise to use an upright position, which will take the least toll and will be fastest to recover from. Some bike setup tweaks can make a (more) upright position easier - from higher handlebars, to moving the seat forwards, to even getting a slightly shorter bike frame (since in the case of mountain bikes, they tend to be longer for greater stability). Finally, while riding you should be looking up, at the horizon practically, not at the cockpit.