Ahhh….the fresh aroma of coffee in the morning is enough to perk you up and feel alive! But how much coffee should we be drinking? Is too much coffee harmful? What are some of caffeine’s effects on the body?
The most commonly used drug in the world isn’t marijuana, alcohol, or even tobacco. It’s caffeine! Caffeine is an ingredient found in coffee and tea, as well as cola drinks, cocoa and chocolate. Caffeine is a stimulant drug that makes you feel more alert. Many people don’t realise that, like many other drugs, including tobacco, caffeine is addictive. This means that when someone stops using the drug they get unpleasant symptoms or withdrawal symptoms. This is why regular coffee drinkers may experience headaches, irritability and fatigue when they stop drinking it.
How can caffeine affect my health? Doctors believe a moderate amount of caffeine won’t cause problems for most people (see the table below for intake levels). But because caffeine is a stimulant, large doses can make some people anxious or cause headaches. Some studies of the effects of caffeine on health suggest heavy caffeine use (eg six cups of brewed coffee or more each day) can make some heart problems worse.
A definite affect of drinking coffee is the diuretic affect of caffeine. Caffeine makes you urinate more and this makes you lose fluid from your body. Obviously with less H2O in the system we can become dehydrated and this leads to headaches and poor biochemical processes’s. So it’s important not to think of caffeine drinks like coffee, tea and cola as good thirst quenchers. If you drink coffee tea and cola, it’s also important to drink plenty of water as well, especially in hot weather and before and after exercise.
Some common questions about coffee and caffeine
Does caffeine cause problems with sleep? Yes, taken before bedtime it can make it harder for some people to get to sleep. It can also make you sleep less soundly.
Is caffeine safe in pregnancy? Many drugs can affect an unborn baby. Some studies have found links between very large doses of caffeine and miscarriage, premature birth and stillbirth. But this isn’t a problem for women who have moderate amounts of caffeine in pregnancy. Doctors now recommend pregnant women have no more than 200mg of caffeine a day. This is about two to four cups of coffee or tea daily – the table below can help you work out how much caffeine you have each day.
How do I know if I’m having too much caffeine? For most of us, around one to two cups of brewed coffee or three cups of tea each day is probably okay. Most doctors believe there’s very little risk of health problems for people who have less than 600mg of caffeine each day (see table below).
Is tea healthier than coffee? The advantages of a cup of tea are that it usually contains less caffeine and also contains anti-oxidants which may help protect against heart disease and cancer. Green tea is especially good! But it can also make it harder for the body to absorb iron from food so it’s better not to drink tea with meals. This is a good thing to remember if you’re female as many women don’t get enough of this important mineral.
Amount of caffeine in common drinks:
Brewed fresh coffee – 80-350mg per cup
Instant coffee – 60-100mg per cup
Decaffeinated coffee – 2-4mg per cup
Tea – 30-90mg per cup
Cola drinks – 35mg per 250ml serve
Cocoa/hot chocolate – 10-70mg per cup
Chocolate bars – 20mg-60mg per 200g
As a rule of thumb, try to limit your caffeine intake to less than 600mg per day.
Caffeine and exercise
Caffeine has three main effects on the body as it relates to exercise. Caffeine acts:
(1) as a stimulus to the central nervous system
(2) to decrease the contractile threshold of a muscle, allowing a smaller stimulus to elicit a muscle contraction
(3) to increase the mobilization of free fatty acids in the blood stream
Free fatty acids are the portion of fat that can be burned as fuel by the muscles, and as an energy resource they are of major importance to marathoners and other distance runners.Due to the increase of free fatty acids that occurs as a result of caffeine ingestion, caffeine was seen as beneficial to long distance runners, especially marathoners.Physiologically speaking, as you run, your muscles use both fat and glycogen as fuel. Theoretically, the body has an unlimited supply of fat for distance running purposes. However, the natural tendencies of our bodies are to use mostly muscle glycogen as fuel in the first 90 minutes of running.
Caffeine increases the use of fat as fuel thus sparing our bodies’ limited supply of muscle glycogen. After about 90 minutes, the glycogen stores can become depleted, causing you to slow down (also known as “hitting the wall”) as your body switches to fat as the primary fuel.
By performing extra long runs (more than 90 minutes in duration), not only will you be able to (1) build thick, new networks of oxygen-carrying capillaries, (2) increase the number and energy-producing capacity of your muscle cells’ mitochondria, (3) safely recruit and train fast-twitch muscle fibers to gain greater endurance potential, but you will also be able to (4) teach your body to begin using more fat as a fuel earlier in your runs, thereby delaying the depletion of your muscle glycogen and ultimately increasing your endurance (your ability to run for a longer period of time).
Therefore, if you could further increase the body’s use of fat as a fuel earlier in your training runs (through caffeine ingestion), you could benefit from being able to train longer distances and race farther before slowing down. This is because delaying the use of glycogen will allow you to maintain a given pace longer before fatigue sets in.
