Blood Pressure
Sleep & hardening of the arteries Blood pressure & cognitive function
Exercise and pre-eclampsia Blood pressure & Alzheimer's
High levels of exercise may cause pre-eclampsia
Up until now, pregnant women have been advised to maintain a moderate level of physical activity throughout their pregnancy in order to help them stay healthy and to keep their blood pressure down. However, recent research (Osterdal et al. Does leisure time physical activity in early pregnancy protect against pre-eclampsia? British Journal of Obstetrics and Gynaecology, 2008) that attempted to prove this, has ended up DISPROVING it!
The study looked at medical data from 85,000 women and it showed that jogging for more than 1 hour and 15 minutes per week doubled the risk of developing pre-eclampsia - a form of high blood pressure that affects 1 in 14 pregnant women and is potentially fatal for mother and baby.
What's more, the researchers found that, as the level of exercise increased, so did the risk of pre-eclampsia. For those performing between 4.5 and 7 hours exercise per week, the risk of developing pre-eclampsia increased by 65% but performing over 7 hours of exercise per week increased the risk by 78%. This means that the overall risk of developing pre-eclampsia is 7% for women doing more than 1h15m exercise, 18% for those performing 4.5h to 7h exercise and 29% if they are doing over 7h exercise per week.
Current guidelines suggest that women maintain a moderate level of activity throughout pregnancy but this research seems to indicate that pregnant women should not perform more than 1h15m of higher intensity activity per week. More research now needs to be carried out to determine what is a safe exercise intensity and duration for pregnant women and whether the mode of exercise plays a part in pre-eclampsia risk too.
Blood pressure and Alzheimer's risk
An analysis of over 10 years of Alzheimer's research has found a significant link between blood pressure and the development of late-onset Alzheimer's (Alzheimer's Australia. Press Release. Latest Medical Finding - Reducing high blood pressure decreases incidence of dementia.). Results showed that successfully treating and lowering high blood pressure can reduce Alzheimer's disease by up to 50%.
This led Dr Michael Valenzuela, the researcher, to state that, "...the number one thing a person can do to help prevent dementia is to have your blood pressure checked regularly and, if it is high, take the right measures to bring it under control."
Dr Valenzuela theorises that high blood pressure reduces the blood flow to the memory part of the brain meaning that the brain cells do not receive enough nutrients and do not have their waste products removed effectively. This can lead to the blood vessels in this section of the brain bursting/bleeding which could set off the development of Alzheimer's.
Lack of sleep hardens the arteries
A recent study from America (King et al. Short sleep duration and incident coronary artery calcification. JAMA, 2008, 300, 2859-2866) has shown that those of us who sleep for less than 5 hours a night may be at an increased risk of developing calcium plaques in our arteries putting us at a higher risk of heart disease and heart attack.
The study found that almost one third of people who sleep less than 5 hours per night developed hardened arteries whereas just one tenth of people who sleep for 6 hours or more will develop this condition. The researchers concluded that, for every extra hour's sleep, the risk of developing hardened arteries dropped by 33%.
There are no firm conclusions as to why this link is evident. It could be due to the fact that blood pressure drops whilst we are asleep so a lack of sleep means that excess strain is placed on the arteries leading to the build up of plaques. Alternatively, it may be that the stress is the cause - stress hormones are linked with lack of sleep and hardening of the arteries.
Whatever the cause may be, the best advice that we can give you is to try to get at least 6 hours sleep per night!
Blood pressure impacts upon cognitive ability
A small study from December 2008 (Gamaldo et al. Exploring the within-person coupling of blood pressure and cognition in the elderly. Journal of Gerentology, 15 Dec 2008) found that high blood pressure may impact upon a person's cognitive ability. The researchers measured the subject's (36 people aged 60 - 87) blood pressure and cognitive functioning twice a day for 60 days.
Results showed that those people with s systolic blood pressure of over 130mmHg suffered a significant loss in cognitive ability when their blood pressure rose due to mental stress. However, subject with systolic blood pressure under 130mmHg did not suffer any decline in cognitive ability in the same situation despie a rise in their actual blood pressure at the time.
Researchers suggest that this study may explain why some people find it hard to function cognitively in high pressure situations. More work needs to be done in this area though as this study was small.