Caffeine after 6 p.m.

Caffeine after 6 p.m.

Caffeine is a central nervous system stimulant. It works by stimulating the brain. It is the most commonly used psychoactive drug in the world. Caffeine is a white in colour bitter-tasting chemical. The most common well-known sources of caffeine are coffee, soda and tea.


People love consuming caffeine-containing foods and beverages. There have been multiple types of research based on the use of caffeine. With each study caffeine gained popularity in terms of proving beneficial for increasing metabolism, preventing Diabetes Type 2, elevating mood and, also acts as an energy source for athletes and fitness enthusiasts. Still, there are certain limitations for the use of the same. Being an important part of our daily food intake, we should be aware of how caffeine affects human physiology. Now, let’s get to know caffeine in detail.


On looking at the history of caffeine, it has been wrapped in several myths and legendary stories. The word caffeine has been derived from the German word “kaffee” and French word “cafe” both of which mean coffee. According to History and Background (2012), the coffee beans were discovered by a farmer in Ethiopia, who observed that his goats became restless and hyperactive after consuming some berries. These berries were later dried and called “coffee beans.” The Discovery and spread of use (2018) talks about the origin of coffee in China where an emperor noticed a distinct colour and fragrance of a few leaves that fortuitously fell in some boiling water. And by the 17th century, it gained popularity in the form of tea/coffee across various countries like Arabian Peninsula (Yemen, Oman, Qatar, Bahrain, Kuwait, Saudi Arabia and the United Arab Emirates), Europe, Egypt, Turkey, Netherlands and America. Coffee now grown in over 50 countries has a distinct flavour varying on the basis of weather conditions, soil quality and rainfall of each place. Coffee originated in India by the 16th century, when a pilgrim brought some berries on his way back from Mecca. But coffee cultivation flourished in India during the British Rule. They started a commercial coffee plant in South India. Similarly, Britishers also commercialised tea estates in Assam. Gradually it gained popularity and spread its wings across India. Today, coffee and tea are grown in Karnataka, Kerala, Andhra Pradesh and Tamil Nadu and almost all states of East India. We are now one of the largest exporters of both tea and coffee across the world.


  • Pederson, D.J. et al (2008) observed when caffeine is consumed in combination with carbohydrates, it provides quick glycogen stores recovery. A study showed that glycogen stores of athletes who ate a combination of carbs and caffeine in their post-activity meal had 66% of more glycogen reserves in their body than the one who didn’t have it. This might also help in relieving post-workout cramps or pain.
  • Ferraro, P.M. et al (2015) stated that caffeine might help in reducing the chances of kidney stones as it acts as a diuretic.
  • One of the widely known effects of caffeine is its mood elevating property. It makes our mind alert acting as a stimulant. Adenosine is a chemical found in our brain which makes us feel drowsy by slowing down the activity of the Central Nervous System. As soon as we are awake, adenosine concentration keeps on increasing with every hour. This makes us feel sleepy by the end of the day.
  • Caffeine makes us alert by binding with adenosine receptors so that they are not read by our brain. Instead, it induces the secretion of Dopamine.
  • Dopamine is a neurotransmitter that sends signals from one part of the brain to other. In its presence, if we read or do anything, our mind remembers it as it keeps our mind alert. Dopamine helps us pay attention and stay focused. It also affects our learning process and the retention power of the brain. Since caffeine is the contributing factor in the release of dopamine it in-turn makes us active and alert.
  • Caffeine might be helpful for people with Migraine. Lipton, R.B. et al (2017) conducted a study which concluded that caffeine therapy may be useful in some primary or secondary forms of a headache. They also stated that caffeine when taken with some pain relieving medications, makes them more effective.
  • In the sports industry, it is one of the popular ingredients used in pre-workouts and intra workouts. This is because it increases the utilisation of fatty acids during exercise as a fuel. It reduces the feeling of exhaustion and increases endurance and stamina.
  • Glycogen is the stored form of glucose. Carbohydrates required by an athlete depends upon the kind of activity he/she is involved in and how rapidly their glycogen stores are depleted. This is the reason why endurance athletes are advised to consume a blend of both simple and complex carbohydrates. Caffeine spares glycogen and averts body to use fats as energy fuel. Within 1 hour of ingestion, caffeine reaches its peak level as a stimulant. 
  • Caffeine also increases blood pressure so if a person has hypotension then a caffeine jolt might prove beneficial. This effect was proved under a study led by Geethavani, G. et al (2014).
  • Dam van, R.M. et al (2006) led a study which statistically showed that regular caffeine intake had curtailed the risk of developing Type 2 Diabetes. 
  • One of the bizarre uses of caffeine is to use it as a colon cleanser in which the colon is injected into the large intestine via rectum and it cleanses all the toxins. This is termed as Caffeine Enema. 
  • A recent German study in Heinrich-Heine-University concluded dose-dependent protective benefits of caffeine which was 4 or more cups of coffee per day to strengthen the heart muscles and lengthen its life. This study was undertaken by Niloofar, A.A. et al (2018).


With so many benefits, caffeine also has some disadvantages attached to it. Caffeine increases acid levels in the body so it might result in heartburn. People with ulcers should not consume caffeine based foods or beverages. Excess consumption of caffeine might make you jittery and cause irregular heartbeats. It might increase the chance of developing hypertension. Regular intake of caffeine might result in addiction and as a result, people tend to consume more of caffeine and caffeine based sugary beverages.

As discussed earlier, it acts as a diuretic. So if a person’s fluid intake is less, it might result in dehydration. Dehydrated cells are unable to absorb nutrients from the food effectively. Caffeine consumption might also lead to insomnia.


Due to these possible adverse effects, people have found an alternative which is referred to as Decaffeination. Nowadays, people choose decaffeinated coffee to keep a check on their caffeine intake. It is prepared by washing green coffee beans in a solvent until the caffeine content is reduced. Post that they are grounded and roasted. This process doesn’t change the other nutritive value of coffee beans but only removes approximately 97-98% of caffeine, which means that decaffeinated coffee is also not 100% caffeine free. Apart from coffee, caffeine is also popular among several products like tea, chocolates, soft drinks, energy drinks, caffeine tablets and in some pharmaceutical anti-depressants drugs. Other popular low caffeine alternatives are latte coffee, latte tea, snack bars, chocolates, yoghurts, breakfast cereals, etc. Caffeine naturally occurs in tea so the longer they are brewed in hot water, higher is the caffeine content. But caffeine from tea is slowly absorbed in our body as compared to caffeine content present in coffee. Tea also contains L-Theanine which is an amino acid that induces calmness and relaxation. People also cherish low caffeine or caffeine-free herbal teas like green tea and black tea.


Now the question arises that with such effects and side effects, how much should be the intake. As per researchers’ guidelines, caffeine intake should not exceed more than 300 mg/day. One serving of Nestle Instant Coffee contains 60-80 mg caffeine. Pregnant and lactating women should avoid caffeine consumption due to its acidic nature and it also decreases the absorption of nutrients from food.


Excess of anything is bad for the body. Caffeine can have some favourable effects on the body until it remains within recommended limits. But caffeine before bedtime or late in the evening is definitely a bad idea. Sportspersons who workout/practice in the evening should consume their caffeine based pre-workouts before 5 PM. Don’t allow caffeine steal your sleep.


  • Effect of caffeine on heart rate and blood pressure. International Journal of Scientific and Research Publications, Vol 4, Issue 2.

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