From gout to asthma: when it all happens

FROM gout to asthma and heart attack, our symptoms – and the likelihood of experiencing an ‘event’ – alter throughout the day, due to changes driven by our body clock. Although still an emerging science, this graphic, left, shows what we know about the average peak times for body experiences in the first 12 hours of the day.

MIDNIGHT: Eczema and psoriasis: intense itching of these skin conditions occurs between 8pm and 2am, peaking near midnight when skin is most porous and loses moisture, becoming more dry and itchy. 1am: Gout pain, caused by crystals of uric acid in the joints, tends to strike between 1am and 5am, peaking around 3am to 4am and coinciding with an overnight drop in body temperature, which may encourage the crystals to form. 2am: Cluster headaches. These excruciatingly painful headaches can start at around 2am, possibly due to abnormal messages from the ‘master’ clock in the brain.

3am: Toothache peaks between 3am and 7am due to changes in pain receptors driven by the body clock.

4am: Asthma symptoms tend to be worse around 4am. Lung function is usually at its best around 4pm, with the lowest flow at 4am, which is worse for asthma, probably due to overactive immune responses in the lung.

5am: Babies are usually born between 1am and 7am, peaking around 4am to 5am. This may be a time that was optimal for our ancestors and linked to the night-time release of the hormone melatonin.

6am: Coughing and other symptoms of lung conditions, such as emphysema and chronic bronchitis, tend to worsen in the early hours, often due to the build-up of mucus in the lungs overnight. Mucus production is also stimulated as an immune response in preparation for the the day.

7am: Joint pain caused by rheumatoid arthritis peaks around 4am to 8am, when more inflammatory chemicals are released in preparation for greater immune protection during the day. 7am is also when osteoarthritis pain and joint stiffness tends to peak. Normally, during the day, joints are cushioned by the elasticity of cartilage which is triggered by circadian rhythm. As we age, this ‘flattens’ and joint-cushioning declines, resulting in pain.

9am: Stroke and heart attack risk peaks between 6am and noon. It is linked to the early morning rise in blood pressure and blood clotting factors.

10am: If you’re a ‘lark’ (someone who likes to rise and go to bed early), migraines tend to occur between 8am and midday. However, ‘owls’ (evening types) suffer in the afternoon and early evening. We know the body clock is connected to migraine, but how is not clear.

11am: Our circadian-driven rise in alertness peaks, having prepared us for the new day and increased activity levels.

Significantly, 11pm is when older people tend to start experiencing incontinence, lasting until the early hours. This is because the circadian rhythm in the hormones that regulate urine production – high in the day, low at night – becomes ‘flattened’ as we age, so that urine production isn’t just confined to the day.