Caffeine has a half-life of about 5 hours. Someone who consumes 40 milligrams (mg) of caffeine will have 20 mg remaining in their system after 5 hours. When do effects peak? Levels of caffeine peak in the blood within about 15–45 minutes of consumption.

Extremely high daily intakes of 1,000 mg or more per day have been reported to cause nervousness, jitteriness and similar symptoms in most people, whereas even a moderate intake may lead to similar effects in caffeine-sensitive individuals (9, 10 ).

Such high levels of caffeine can cause serious health problems and possibly death. Although caffeine use may be safe for adults, it’s not a good idea for children. Adolescents and young adults need to be cautioned about excessive caffeine intake and mixing caffeine with alcohol and other drugs.

Caffeine is well absorbed by the body, and the short-term effects are usually experienced between 5 and 30 minutes after having it. These effects can include increased breathing and heart rate, and increased mental alertness and physical energy. Depending on the individual, these effects can last up to 12 hours.

Long-term effects at this level may include chronic insomnia, constant anxiety, depression, and stomach problems. It can also cause high blood pressure or make high blood pressure worse.

What you can do to feel better

1. No more caffeine. Don’t consume any more caffeine today.
2. Drink plenty of water. Caffeine is a diuretic, which means that you need to drink extra water to make up for what you’re peeing out.
3. Replace electrolytes.
4. Take a walk.
5. Practice deep breathing.

Six hours after caffeine is consumed, half of it is still in your body. It can take up to 10 hours to completely clear caffeine from your bloodstream.

Caffeine can cause a short, but dramatic increase in your blood pressure, even if you don’t have high blood pressure. It’s unclear what causes this spike in blood pressure. Some researchers believe that caffeine could block a hormone that helps keep your arteries widened.

Here are a few ways to get rid of caffeine jitters quickly:

1. Water. An effective way to get rid of your jitters is to flush out your system with water.
2. Exercise. You just crossed the caffeine line, which probably means you can’t sit still.
3. Wait it out.
4. Sip on some herbal tea.
5. Amp up your Vitamin C game.

An excessive consumption of coffee or caffeinated beverages can suddenly increase blood sugar levels, which can lead to blurred vision or spasms of the eyelid (jumping eye). Drinking too much caffeine can also cause a burning sensation and may make your eyes a little tingly.

Internal vibrations are thought to stem from the same causes as tremors. The shaking may simply be too subtle to see. Nervous system conditions such as Parkinson’s disease, multiple sclerosis (MS), and essential tremor can all cause these tremors.

Shaking and tremors Your body prepares to deal with the stressor, interpreting the anxiousness as a signal that you’ll need to stand your ground or escape from danger. Your muscles become primed to act, leading to a trembling sensation, twitching, or shaking. Tremors caused by anxiety are called psychogenic tremors.

If you suddenly feel weak, shaky, or lightheaded—or if you even faint—you could be experiencing hypoglycemia. A headache that comes on quickly, weakness or tremor in your arms or legs, and a slight trembling of your body are also signs that your blood sugar is too low.

Good choices are crackers and peanut butter, yogurt and fruit, half a turkey sandwich, or a bowl of whole grain cereal with milk. A snack at bedtime can help keep blood sugar levels normal during the night.

Chronic fatigue syndrome Chronic fatigue syndrome (CFS) is a condition that causes you to feel exhausted and weak, no matter how much rest or sleep you get. It often causes insomnia. Because your body doesn’t feel rested or replenished, CFS can also cause aches in the muscles and joints throughout your body.

Low blood sugar triggers a “must eat now” type of hunger – we feel shaky, weak, lightheaded and irritable because our body wants us to correct the problem.

Emergency symptoms of type 2 diabetes Hypoglycemia occurs when there are dangerously low levels of blood sugar. For people with type 2 diabetes, only those who are on medications that increase the body’s insulin levels are at risk for low blood sugar. Symptoms of hypoglycemia include: shaking.

Other symptoms of hypoglycemia are caused when not enough glucose gets to the brain; in fact, the brain is the organ that suffers most significantly and most rapidly when there’s a drop in blood sugar. These symptoms include headache, extreme hunger, blurry or double vision, fatigue, and weakness.

Whether you’re at home or at a restaurant, here are the most diabetes-friendly beverage options.

1. Water. When it comes to hydration, water is the best option for people with diabetes.
2. Tea. Research has shown that green tea has a positive effect on your general health.
3. Coffee.
4. Vegetable juice.
5. Low-fat milk.

Not everyone’s blood sugar (glucose) tumbles as quickly as Jeff’s, but there is plenty of research affirming that a healthy diet like the Pritikin Eating Plan combined with daily exercise can profoundly reduce blood sugar levels in just two to three week’s time.