A circadian rhythm is roughly a 24 hour cycle of our internal body clock; it’s very important for controlling when we eat, sleep and numerous other factors. It’s usually controlled by external factors with light being the most common. Circadian rhythm disorders usually affect the timing of sleep which can greatly affect a person’s social and work life.
For those of you that read our Circadian Rhythm Disorders: Part 1 you would have found out about two common circadian rhythm disorders – delayed sleep phase disorder (DSPD) and advanced sleep phase disorder (ASPD). In part two we will be looking at the other two common disorders – free running disorder (FRD) and irregular sleep-wake rhythm disorder (ISWRD).
Free running disorder (FRD)
This rare disorder is also known as non 24-hour sleep phase which affects around 0.03% of the population. FRD lasts longer than the usual cycle of a circadian rhythm which typically lasts around 24 hours. The sufferer has no consistent bedtime pattern as each cycle varies; where one cycle may be an extra two hours, the following day may be an extra three hours which makes it very difficult for the sufferer to predict in advance when they may fall asleep. The circadian rhythm of people with this disorder has no external cues of light and darkness which may explain why sufferers can sleep around the clock. The cycle will never make the person go to bed earlier than the day before, for example if one night they went to bed at 10pm and woke up at 6am, the following night they may not go to bed till 12am and wake up at 8am; the later nights will keep moving around the clock until the time is back round to 10pm.
The sufferer is unable to adjust day to day which can lead to psychological problems because they are unable to retain relationships with people and find it difficult to work in a typical 9 till 5 job. FRD can lead to other health problems such as:
What is the treatment of FRD?
If you are having trouble sleeping you should always contact your doctor first; they will be able to look over your symptoms and hopefully be able to pick up on any signs that you are suffering from FRD. If they suspect that you’re suffering from this disorder they may refer you to see a sleep specialist; this may involve an overnight sleep study to see if there are any patterns in the way you sleep. Furthermore they will try and help your body clock to run like a healthy cycle by introducing bright light therapy and melatonin into your daily routine. Once you have went to bed at your desired time, for example 10pm, you will have to follow a routine; on a morning you will expose yourself to bright light either from the natural sunlight or from a bright light box, you are usually advised to use the bright light for two hours every morning; this can help you feel more alert and refreshed on a morning. On an evening about an hour before you go to bed you can take melatonin to help you feel sleepy and to steady the circadian rhythm. However this routine doesn’t work for everyone and the use of medication doesn’t always improve the quality of sleep which can lead to daytime tiredness and add to the stress; some sufferers are happy to follow their ever-changing rhythms and can adapt to the daily change.
Irregular sleep-wake rhythm disorder (ISWRD)
People who suffer from this very rare disorder sleep numerous times throughout the day and night rather than having just one main sleeping period. The sleep periods can occur up to four times a day and can last anywhere from one to four hours; according to Zee & Vitiello, 2009 the longest sleep period is usually between 2am and 6am. The sufferer has no noticeable sleep pattern although they still sleep the same amount of hours as a person with a healthy circadian rhythm. Like FRD, this disorder affects both the work and social life of an individual and they usually have no daily routine or set schedule, hence why they may sleep for short bursts throughout the day. A sufferer can be seen as someone who takes long naps throughout the day, to an extent this is true; in the long-term it can be bad for your health as you’re spending less time in the deep sleep stage which is an important time for your body to recover and replenish. The main symptoms of irregular sleep-wake rhythm disorder are:
Excessive daytime sleepiness – due to the sufferer sleeping short amounts of time they will feel tired and groggy throughout the day.
Insomnia – this can be from waking up too soon before getting enough sleep or the inability to fall and stay asleep.
Poor quality of sleep – the period of each cycle is usually never longer than four hours of sleep which means the sufferer spends less time in the deep sleep stages resulting in a poor night’s sleep.
Increase the risk of depression – if you sleep during the day you may miss out on social activities which can leave you feeling isolated and could pose a threat to existing relationships.
The treatment of ISWRD is very similar to the other circadian rhythm disorders. You should always visit your doctor first who will check your symptoms; if they feel you are suffering from this disorder they may refer you to see a sleep specialist. They will guide you on bright light therapy which should be used in the morning either by natural sunlight or a bright light box and melatonin which should be used at night to make you feel sleepy. Your sleep patterns may be monitored using an actigraph which is a device worn like a watch to track your sleep-wake cycles. Other methods which your doctor will recommend if you want to keep your circadian rhythm running as normal as possible is to follow strict sleep hygiene and participate in the same activities everyday. There is always a risk of falling back into old patterns with any circadian rhythm so you have to be strict with yourself; set your alarm for the same time everyday even if you don’t need to be anywhere and going to bed around the same time every evening.
Remember, if you notice any disturbances or abnormalities in your sleep pattern you should inform your doctor. However, you can help your doctor diagnose your condition by keeping a sleep diary for two weeks; this should include when you woke up and went to bed, any disturbances, how you felt etc.