There's a lot of people saying the same things here so i thought i'd add some pics to helps the understanding.
The vast majority of numbness is caused by compressive forces on the nerves in the palm of the hand, mainly the Ulna nerve. These compressive forces may be time spent in one position or vibrations from terrain or big potholes/heavy landings. Basially they all have the same effect on the wrist, they cause compression of the nerve against the carpal bones (note, this is different from carpal tunnel syndrome).
Because you may be dealing with nerves you need to remember they each nerve starts by branching off from the spine, so with the nerves the feed the arms and wrist you would be wise to get your neck, shoulder and elbow checked. These nerves specifically leave the neck from C5,C6,C7,C8 and T1 where they go throught the Brachial Plexus into the shoulder and arms.
If your neck position is bad then this sould cause a problem anywhere further down the arms into the wrist and hand.
any compression of the Brachial plexus from resicted breathing patterns, bad posture and/or tight muscles would have an effect further down the arm. Same can be said at the shoulder, elbow and wrist.
To Answer the Thread question, Gloves would be the cheapest and for most a solution to the problem. If it persisits then it would be worth seeking a form of manual therapy, i.e., Oesteo, Chiro, physio, injury rehab, etc.