If you're reading this online, stop. Lift your hand and let it relax with the palm upwards in front of you. Look at it. If you spend hours each day typing you'll certainly notice the palm of your hand is concave, with the fingers curling round. As you get older, this will  happen even more, and can lead to arthritic pain and reduced mobility.

"I remember an architect in one class," recalls Pam Horton, a teacher-trainer for the British Wheel of Yoga. "He said that when he got up in the morning his fingers were curved over. He had to manually straighten them."

Horton recommends a very easy exercise to prevent long-term damage.

"Put your left hand out with the palm facing upwards, separating your left thumb out to the side," she says. "Keep the forearm, wrist and palm out in a straight line from the elbow.

"Now turn your right hand palm-down," Horton continues, "and make a kind of crocodile's mouth with the thumb as the lower jaw, and the four fingers as the upper jaw. Grip the fingers of your left hand in this mouth, with your right thumb forming a supportive beam beneath the four knuckles of your left fingers where they join the hand. Without bending your wrist, gently bend the fingers down beyond the horizontal and hold them there for 12 seconds. Release and then repeat. Now reverse the process and do the same stretch twice on the other hand."

Horton recommends doing this three times a day, although you could do more, or fewer, depending on how much time you feel you spend with your hands curved over.