Showing posts with label Sleep. Show all posts
Showing posts with label Sleep. Show all posts

Saturday, 23 October 2010

Caffeine

There are many myths surrounding caffeine, caffeine intake and the risk associated with its use, so here I will try to explain and dispel some of those myths.

What is caffeine?

Chemically speaking, pure caffeine is a plant-based alkaloid which stimulates the central nervous system of any creature that ingests it. In nature, caffeine serves as a form of pest control for certain plants such as cacao trees, coffee shrubs, yuba mate and tea trees. The caffeine causes insects and other pests to collapse from the effects of over-stimulation.
Caffeine, also known as guaranine, mateine or theine depending on the source plant, is considered a psychoactive drug. However, it has not been designated a controlled substance, so its use in teas, coffees and sodas is not illegal. Coffee beans contain a significant amount of caffeine, while tea leaves and yuba mate plants contain less. Cocoa beans also contain caffeine, but they contain much higher levels of another alkaloid called theobromine.
When caffeine is removed from the source plant and reduced to its most natural state, it forms a white powder. This powdered form of caffeine is actually very bitter, which is why many beverages containing caffeine also contain copious amounts of sugar or other sweeteners.


Origins


The Coffee Science Information Centre reports the coffee tree probably originated in the province of Kaffa, in the area known today as Ethiopia. There is no real evidence to show when or how it was first discovered that a brew could be made from the bean (or seed) within the fruit of the coffee bush, but it is thought that before coffee was ever enjoyed as a drink; native people may have chewed the ripe berries and beans as a food. There is evidence that coffee trees were first cultivated on monastery gardens over 1,000 years ago in order to keep monks awake during long periods of prayer, with commercial cultivation following after that.


Caffeine the stimulant


Caffeine acts as a mild stimulant of the central nervous system, and as such can have an effect on sleep, mental performance, alertness and anxiety.

 
Sleep. If you have any trouble sleeping caffeine consumption should cease after lunch. This is because caffeine has a half life of around six hours, meaning that six hours after you last coffee (tea, cocoa etc) half the amount of caffeine will still be in your bloodstream. If you have a cup of coffee in the evening when the body start producing melatonin (the sleep hormone) the stimulant effect will trigger the release of cortisol (the wake up hormone). This will release glycogen (sugars) into your bloodstream in readiness for daytime activity; in effect your body will think it is daytime, time to get up and start work activities.


Physical performance. Vanderbilt Education and Psychology reports that caffeine can help burn more fat and less carbohydrates for energy. Glycogen is the main fuel for muscles, but fat is the most abundant resource that the body uses for energy. Caffeine enters the body and forces the working muscles to utilize as much fat as possible. This delays the immediate depletion of glycogen.
This means that in the first 15 minutes of exercise caffeine has the potential to reduce the loss of glycogen by 50%. When this happens, the saved glycogen can be used for the remainder of the workout where normally it would be entirely depleted.
Vanderbilt also suggests that caffeine may have the ability to strengthen muscle contractions. By transferring calcium, sodium and potassium in the cells, membrane permeability increases. This in turn results in more powerful muscle contractions.


In the 2000 Olympics a urinary test above 12mg/litre (8 cups of coffee) was perceived by the IOC as a deliberate attempt to gain an advantage over the competition. Therefore caffeine is seen by the IOC as any other illegal drug.


Cancer and Health


There have been many myths surrounding the link between caffeine and cancer – including urological, pancreatic and breast cancer. In addition caffeine has been linked to heart disease, high blood pressure and cardiovascular problems. There is currently so proven link to any of these problems. Indeed the British Coffee Association reports that caffeine may even protect against liver cancer.
Caffeine although not proven to be a link to any of the above health problems can cause (apart from sleep deprivation) nausea, cramping, anxiety, fatigue and headaches. Factors such as metabolism, consumption and frequency of use have to be taken into account, so how much is enough?
Both the Coffee Science Information Centre and British Coffee Association (BCA) suggest that 4-5 cups of coffee per day is perfectly safe for the general population and may even have some health benefits.

Pregnancy

The BCA website states that the Food Standards Agency, The Centre for Pregnancy Nutrition and The Royal College of Midwives are agreed that 2-3 cups of coffee is safe during pregnancy and breast-feeding and that there is no research to suggest otherwise.
Their factsheet can be found here and contains information regarding levels of caffeine in instant coffee, filtered coffee, chocolate, energy drinks etc. This is important reading beause above a certain level there is a greater risk of miscarriage.


Coffee facts

To make a roated pound of coffee it takes around 2000 Arabica coffee cherries. With two beans per cherry- this means it takes 4000 beans per pound of coffee.

 
It takes 42 beans to make an espresso.

 
Sir Francis Bacon once said "The drink that comforteth the brain and heart and help digestion".

Sir James Mackintosh said "The powers of a man's mind are directly proportionate to the quantity of coffee he drinks".

Edit.

I have just had some interesting statistics given to me by a friend who posts on the Martial Arts forum Martial Arts Planet 

It is in regard to the half life of caffeine and was taken from Wikipedia.

The biological half-life of caffeine is the time required for the body to eliminate one-half of the total amount of caffeine. It varies widely among individuals according to such factors as age, liver function, level of caffeine-metabolising enzymes in the liver, pregnancy, medication and habits such as smoking.

* In healthy adults, caffeine's half-life is approximately 4.9 hours.

* In women taking oral contraceptives, this is increased to 5–10 hours.

* In pregnant women the half-life is roughly 9–11 hours.

* Caffeine can accumulate in individuals with severe liver disease, increasing its half-life up to 96 hours.

* In infants and young children, the half-life may be longer than in adults; the half-life in a newborn baby may be as long as 30 hours.

* Other factors such as smoking can shorten caffeine's half-life.

Post by Simon Sheridan

Saturday, 4 September 2010

Circadian Rhythm

ARE YOU GETTING ENOUGH SLEEP

It is all to easy when training is not going so well to blame diet, training techniques, age, time factors, lack of equipment, places or partners to train with and so on. But how many of us look at or understand our sleep patterns, or how a good sleep pattern can benefit our health and cure those aches and pains that even the doctor could not help?

Years ago when we all lived outside we would have gone to bed when it was dark and got up with the sun. Those living a tribal existance will still be doing just that, as will many wild animals. This is the natural sleep/wake process, but why and how does it occur?

Circadian Rhythms are physical, mental and behavioral changes that result from the movements of the sun and planets following a 24 hour cycle and affecting nearly all living creatures including plants. Circadian Rhythms are produced by natural factors within the body, but they are also affected by signals from the environment. Light is the main cue influencing Circadian Rhythms, turning on or off genes that control an organisms' internal clocks.




The above illustration is an overview of the human circadian biological clock with some physiological parameters. Many of our hormones are produced in tune with the cycle of the sun. Stress activating hormones cortisol are produced as the sun rises and peak around mid-morning. As the day progresses, the level of stress hormones decrease. The body then begins to increase production of growth and repair hormones melatonin as the sun goes down. Our bodies are designed to wind down from sunset until about 10.00 pm, when sleep and physical repair should begin. Psychological repair takes place predominantly from about 2.00 am to 6.00am.


DISRUPTED SLEEP/WAKE CYCLES


A disrupted sleep/wake cycle can lead to adrenal fatigue. The adrenal glands produce a hormone called cortisol, which is an activating hormone released in response to stress. This activates the body in preparation to work or movement. In addition, if you go to bed after midnight you’ve already missed two hours of your psychological repair cycle. This long term can lead to musculoskeletal injuries, headaches, as sagging personality and neurological disorders.


TIPS FOR A GOOD SLEEP/WAKE CYCLE


1. Get to sleep by 10.30 pm. Wind down before you go to sleep. Going to bed at 10.00 pm and reading until 11.00pm does not count.
2. Minimize exposure to bright lights, two hours before going to bed (including TV.)Try dimmer switches or candles.
3. Sleep in a room that in completely dark.
4. Avoid caffeine, sugar and nicotine after lunch. These are stimulants which trigger the release of cortisol.
5. Drink plenty of water. If dehydrated the body thinks it is in stress. Again more stress hormones, which are awakening hormones.

Another thing to understand is that the body cannot tell the difference between different types of stress. So if it is bills you cannot pay, an arguement with a partner of a fall down the stairs, it is all just stress as far as your body is concerened. So stress releases cortisol, which we now know as the wake up hormone, therefore it is of upmost importance that a calm frame of mind is reached before going to sleep.

Circadian Rhythm is closely linked to Entrainment which will be the subject of our next blog.

Post by Simon Sheridan