Discussion
Most participants recalled being awoken from sleep by cramps and cramps occurring at irregular times or in the middle of sleeping time. These findings suggest that night-time muscle cramping may profoundly affect quality of sleep. Most participants also reported experiencing calf-muscle soreness in the days following cramp. There are anecdotal reports in the literature of discomfort persisting for hours following night-time muscle cramp [15]. This is the first study to demonstrate the prevalence and lengthy duration of ongoing pain.
Mean usual pain intensity of night-time calf cramp was 66 mm on a 100 mm visual analogue scale and most participants also experienced night-time muscle cramping of other muscles and day time muscle cramping. The severity and high frequency of cramps reported
by participants are despite current therapies. As most participants reported experiencing some help from treatment, it is expected that frequency and severity of cramp would be higher if current treatments were withdrawn.
Median reported age of first cramp (50 years) in this sample was younger than previous reports in the literature. Of 86 respondents to a United Kingdom (UK) postal survey who reported suffering from rest cramps, the mean age of cramp onset was 60 years (95%CI: 57 to 63) [15]. This result is reflected by a second UK survey of 182 people over 65 years of age who experienced leg muscle cramp. 80% of participants reported cramp onset after 55 years of age [7]. The younger age of cramp onset in the present sample might reflect the inclusion of adults of all ages or differences in exposure to cramp precipitants (e.g. climate) between the UK and Australia. Indeed one participant stated that cramps ‘started when I moved from England at 67 [years of age]’, although this could be coincidental.
Advice-seeking behaviour in our sample was more common than in previous reports in the literature. In a UK survey of 182 people over 65 years of age who experienced leg muscle cramp, only 40% sought advice from their General Practitioner about their cramp (contrast to 63% in our sample) [7]. This is similar to the results of a similar survey in England of people randomly selected from a General Practitioner’s Register [15]. Interestingly, of all participants who had not reported cramp to a General Practitioner, 31% described their cramps as being very distressing or a major nuisance [15]. Despite the present finding of more common advice seeking, only two participants reported achieving cramp prevention with treatments recommended. Both reports related to quinine, which doctors in Australia are now discouraged from prescribing for muscle cramps.
The most commonly reported treatment used to prevent recurrent cramp was magnesium supplementation (used by 58% of participants). Most participants perceived the magnesium supplements as being ‘useless’ or only ‘a little help’. This is consistent with randomised trials that found that, while magnesium supplementation