London - Any hospital casualty doctor will tell you the revolving doors really start spinning after midnight as patients with severe asthma, acute heart failure, and COPD (chronic obstructive pulmonary disease) start being admitted to hospital with life-threatening problems.
This is also the time when waiting times are longest - official statistics show patients visiting Accident & Emergency (A&E) face much longer delays in the early hours compared to the daytime or evening.
Lack of staff and specialist services are largely to blame, and there have been growing calls for high-quality emergency care to be available seven days a week.
But there are also physiological reasons why illnesses deteriorate at night - not least the fact that you’re lying down. Here we look at some of the conditions which deteriorate when dark descends, and how to reduce symptoms.
Night-time coughing is common in people with asthma, with 61 percent saying it prevents them sleeping well.
Every day in the UK, 200 people with asthma are hospitalised because they are struggling to breathe - many arriving for emergency treatment during the early hours.
“People with asthma tend to experience worsening symptoms at night, including breathlessness and wheezing, which may lead to A&E attendance,” says Deborah Waddell, a specialist asthma nurse at Asthma UK.
“There are theories this could be related to the body’s circadian rhythm (24-hour cycle). Levels of hormones such as the stress hormone cortisol change at night, which impacts airways.
“After midnight breathing rates are at their slowest, resulting in less effective transfer of oxygen into the bloodstream and carbon dioxide out of the body through the lungs.”
Bedrooms are also full of common asthma triggers - including house dust mites in bedding, mattresses, soft toys, carpets and curtains.
Ventilation is often poor - made worse by double-glazed PVC windows which do not permit draughts - and mould spores proliferate in warm, damp environments.
A horizontal posture may contribute. ‘The cough, when lying down, could be due to pressure on the diaphragm (the muscle separating the chest and abdomen), especially if someone is overweight, has gastric reflux, or post nasal drip, where mucus runs from the nose into the back of the throat.’
Research shows people who have personal asthma action plans - detailing steps to take when symptoms worsen - are four times less likely to be admitted to hospital as an emergency, Deborah Waddell says.
Around 10 million Britons suffer from arthritis, which causes painful inflammation in cartilage and bone in the joints. The most common form is osteoarthritis due to wear and tear, often in the knees, hips and hands -this usually affects the over-50s.
“Periods of prolonged rest, like sleep, can make pain worse,” explains Philip Conaghan, professor of musculo-skeletal medicine at the University of Leeds and spokesperson for Arthritis Research UK.
“We’re not sure why, but it’s probably due to joint linings becoming congested with excess fluid used to bathe cells, and protein waste products when joints are immobile for a length of time.
“These are always present but are usually flushed away from joints and excreted by the body’s mechanisms. This process slows down at night, leading to stiffness and pain which can wake people.”
Other musculoskeletal conditions such as bursitis in the shoulder - inflammation of tiny fluid-filled sacs responsible for smooth action of joints and tendons - can become more uncomfortable at night. “The pressure of the person’s weight causes problems, and turning over can be painful.”
Disturbed sleep patterns due to pain can cause fatigue and depressed mood, making daytime symptoms worse. Professor Conaghan advises people with night-time arthritis pain to talk to their GP about swapping from short-acting pain killers, such as paracetamol, to ones that are long lasting.
“If you are getting severe pain in the middle of the night, see your GP and discuss your concerns,” he says.
Waking drenched in sweat is a common symptom of the menopause, caused by the body’s inability to regulate body temperature.
“We’re not sure about the mechanism but it seems the hormone oestrogen, which falls during the menopause, plays an important role in the functioning of the hypothalamus, the temperature regulation system within the brain,” says Dr Edward Morris, a consultant obstetrician and gynaecologist at Norfolk and Norwich University Hospital.
Night sweats are similar to hot flushes in daytime, but they can feel worse. “When in bed, fully insulated by your duvet, you prevent heat loss,” he explains.
“You’re also asleep, so not aware your temperature is rising until quite a long way down the process. If women are awake during the day when the same thing happens, they simply open a window or remove clothing.”
As well as hormone replacement therapy, which boosts oestrogen levels, remedies include “icing” bedding - popping pillows and sheets in the freezer for an hour before bed - and a well-ventilated bedroom.
One of the most painful types of headache, cluster headaches (also known as alarm clock headaches) typically occur around 2am.
“These are excruciating headaches which can occur at the same time each night. They are so painful they are sometimes known as suicide headaches because people who have them literally want to die,” says Dr Andy Dowson, director of headache services at King’s College Hospital and chairman of Migraine Action’s medical board.
In fact, 50 percent of people who suffer from migraines - first cousins of alarm clock headaches - say that their condition regularly wakes them from sleep during the night.
“This may be related to sleep cycles; when people move between periods of deep sleep, rapid eye movement sleep (REM), and almost waking,” says Dr Dowson.
The area at the bottom of the brain, known as the brain stem, is involved in regulating this sleep cycle and it also plays a role in influencing migraine. “In trials we have found that the early stage of migraine originates in the hypothalamus, which is in the brain stem,” says Dr Dowson.
Common triggers include skipping meals, certain foods and bright or flickering lights. Unfortunately some triggers, such as changes in weather, may bring on migraine attacks but can’t be avoided.
Medications that make migraine less likely to occur include anti-depressants, beta-blockers and anti-histamines. In 2010 the National Institute for Health and Care Excellence approved the use of Botox as a preventative for chronic migraine.
When an attack has started, a class of drugs called triptans (available over the counter) can help to alleviate the symptoms.
Around half of heart attack deaths occur within one hour of the attack, and most heart attacks occur in the early hours of the morning, from 4am onwards - when A&E staff levels are lower.
Early morning heart attacks are linked to the platelets in the blood becoming stickier and more prone to clotting.
This is possibly because of overnight fasting or hormonal changes linked to the body’s 24-hour clock.
“Additionally, the effect of medication taken the day before starts wearing off at this time. The combination of effects means heart attacks are more likely in the hours before dawn,” explains Martin Cowie, professor of cardiology at Imperial College, London.
Taking aspirin daily helps make platelets less sticky; taking high blood pressure drugs at night could help, but speak to your doctor before changing your routine.
Reflux of stomach acid into the throat is a common cause of indigestion and heartburn.
It happens when the muscular ring (sphincter) at the lower end of the gullet relaxes too much, allowing the stomach’s acidic contents to flow back up.
It doesn’t necessarily mean the valve is faulty - smoking and pregnancy hormones (which relax all muscles in the body) can cause it to relax, while eating too much at one time can make the valve open, say researchers at the Mayo Clinic in the US. If you are susceptible, reflux can worsen at night because of gravity - being horizontal makes it easier for stomach contents to pass sideways into the throat. Elevation can prevent this. Tim Worthington, a consultant gastrointestinal surgeon at the Royal Surrey County Hospital in Guildford, suggests using a pillow to prop yourself up.
Lifestyle changes, such as not eating too late at night, sticking to a low-fat diet, avoiding caffeine, alcohol and acidic foods, can help.
Over-the-counter remedies tend to contain calcium carbonate or foaming agents that neutralise acid in the stomach.
Prescription drugs reduce stomach acid production - these include H2 receptor antagonists (Ranitidine), proton pump inhibitors (Omeprazole) and anti-acid medication. In very serious cases, surgery can tighten the sphincter.
Many people say symptoms of viruses such as shingles and colds are worse at night. A study published in 2008 in the Journal of Pain and Symptom Management showed pain from shingles, caused by the same virus as chicken pox and affecting older people, does worsen at night.
Shingles pain can lead to unintentional weight loss, sleeplessness, depression and disability.
“It is not clear why shingles pain gets worse at night, but it could be to do with levels of neurotransmitters, chemicals that transmit signals from a neuron to target cells, and hormones involved in pain perception, rising at night,” says John Oxford, a professor of virology at Queen Mary College University of London.
He adds that people can become more anxious at night, which amplifies pain sensations. With colds, he says, the explanation may be more prosaic. “The lining of your airways constantly carries debris and fluid out of the lungs into the throat. This process becomes less effective because you’re horizontal, causing congestion and coughing.”
For shingles, calamine lotion and anti-histamines (a medicine often used to treat allergies) may prevent itching, while paracetamol can help to reduce painful symptoms.
Some shingles pain may be eased by tricyclic anti-depressants because they affect levels of certain chemicals in your body.
Around 750 000 Britons suffer from heart failure, where the heart is too weak to pump enough blood around the body.
When the heart can no longer pump out enough of the blood it receives from the lungs, fluid builds up in the chest, known as acute heart failure, which can be life-threatening.
Patients with acute heart failure are most likely to need emergency hospital treatment at around 3am.
“Heart failure patients often have congestion of fluid in their legs and ankles during the day,” explains Professor Cowie. “If they go to bed at 10pm and lie horizontally, this gradually moves into the chest.
“Three to five hours later, pressure in the blood vessels has built up so much it can force fluid through the lung tissue and into airways.” Sleeping propped up on pillows can help.
The problem is that if you need to go to hospital, though you’re more likely to see an experienced consultant after midnight than you would have been ten years ago, “you may not see a specialist when you need it, which can make a big difference to outcomes,” says Professor Cowie.
Chronic obstructive pulmonary disease (COPD) describes a collection of conditions causing lung damage, including chronic bronchitis and emphysema, causing inflammation in the lungs, often along with permanent damage to the airways.
In a recent study, 76 percent of COPD patients reported frequent night-time wakening because symptoms worsened at night.
Studies have found less air passes through lungs during deep sleep, and dropping body temperature at night affects lung function.
The body also responds less efficiently to increasing carbon dioxide levels in the blood during sleep, so breathing rates do not rise in the same way as during the day to expel it from the body.
Excess carbon dioxide eventually causes someone to wake up, often gasping for breath and “oxygen-deprived”. This leads to exhaustion and worse symptoms during the day.
Dr Nick Hopkinson, spokesman for the British Lung Foundation and a consultant chest physician at the Royal Brompton Hospital, London, says: “Most patients don’t find they’re breathless when they go to bed, but if they wake out of breath, it suggests their COPD is getting worse or could indicate another condition exacerbating symptoms, such as heart failure or asthma.” Keeping the room cool and propping themselves up with pillows can help. - Daily Mail