Exercises to Prevent Nighttime Leg Cramps Have you suffered from sudden spasms, or tightening, of muscles in the calf (sometimes in thigh and foot) at bedtime or rest? There is a chance you might be suffering from Nighttime Leg cramps.A cramp pain typically lasts a few minutes. In some cases it lasts just seconds, but in some cases it lasts up to 10 minutes. The severity of the pain varies. The muscle may remain tender for up to 24 hours after a leg cramp. Leg cramps usually occur when you are resting - most commonly at night when in bed.