Quiz of the Day
Health & Wellness
Sunday, 31 May 2026
World No Tobacco Day — health milestones, body facts, wellness trivia
1. How many chemicals are found in cigarette smoke?
- About 4,000
- About 2,000
- About 500
- Over 7,000
Cigarette smoke contains over 7,000 chemicals, of which at least 70 are known carcinogens. These include arsenic, formaldehyde, lead, and hydrogen cyanide. Despite this, tobacco was once prescribed by doctors — in the 1950s, adverts featured physicians recommending specific cigarette brands.
2. How long does it take for the heart rate to drop after quitting smoking?
- 20 minutes
- 1 week
- 1 month
- 24 hours
Within just 20 minutes of quitting, heart rate and blood pressure begin to normalise. After 12 hours, carbon monoxide levels in the blood return to normal. After 1 year, heart disease risk drops by 50%. After 15 years, the risk is the same as a non-smoker.
3. How many bones are in the adult human body?
- 256
- 186
- 206
- 306
Babies are born with about 270 bones, but many fuse together as they grow. The smallest bone is the stapes in the ear (3 mm), and the longest is the femur (thigh bone). The hyoid bone in the throat is the only bone not connected to any other bone.
4. What organ uses about 20% of the body's total energy despite being only 2% of body weight?
- The brain
- The kidneys
- The liver
- The heart
The brain consumes about 20 watts of power — enough to run a dim light bulb. It contains roughly 86 billion neurons, each connected to up to 10,000 others. Your brain generates enough electricity to power a small LED. It also cannot feel pain itself, which is why brain surgery can be done while the patient is awake.
5. What was the first successful human organ transplant?
- Kidney transplant in 1954
- Lung transplant in 1983
- Liver transplant in 1963
- Heart transplant in 1967
Dr Joseph Murray performed the first successful kidney transplant between identical twins Ronald and Richard Herrick in Boston. Richard lived eight more years. Murray won the Nobel Prize in 1990. Today, a kidney transplant takes about 3 hours and the organ can survive outside the body for up to 36 hours.
6. How many litres of blood does the average adult heart pump per day?
- About 7,500 litres
- About 1,000 litres
- About 15,000 litres
- About 4,000 litres
The heart beats about 100,000 times a day, pumping roughly 7,500 litres of blood. Over an average lifetime, that is about 2.5 billion beats and enough blood to fill over 200 train tanker wagons. The heart generates enough pressure to squirt blood 9 metres across a room.
7. Which country was the first to introduce a ban on smoking in enclosed public places?
- United States
- Ireland
- Bhutan
- Norway
Ireland banned smoking in all workplaces, including pubs and restaurants, on 29 March 2004 — the first country in the world to do so. Many predicted economic disaster for pubs, but air quality in bars improved by 83% within a year and hospitality industry employment actually increased.
8. How much sleep does the average adult need per night for optimal health?
- 9-10 hours
- 7-9 hours
- 6-7 hours
- 5-6 hours
Sleeping less than 6 hours per night increases the risk of heart attack by 20% and makes you four times more likely to catch a cold. The record for the longest time without sleep is 11 days (264 hours), set by Randy Gardner in 1964. He experienced hallucinations and severe cognitive impairment.
9. What percentage of the human body is water?
- About 75%
- About 60%
- About 40%
- About 50%
The brain and heart are 73% water, lungs are 83% water, and even bones are 31% water. You can survive about three weeks without food but only about three days without water. By the time you feel thirsty, you are already about 1-2% dehydrated.
10. Who discovered penicillin, the first widely used antibiotic?
- Louis Pasteur
- Alexander Fleming
- Joseph Lister
- Robert Koch
Fleming noticed mould killing bacteria on a petri dish he had left by an open window in 1928. He called it 'penicillin' but could not purify it. It took Howard Florey and Ernst Chain another decade to develop it into a usable drug. It saved an estimated 200 million lives in the 20th century alone.
11. How fast do nerve impulses travel in the human body?
- About 120 mph (up to 268 mph)
- About 50 mph
- About 5 mph
- About 500 mph
The fastest nerve signals (alpha motor neurons) travel at up to 268 mph, while pain signals travel much slower at about 2 mph — which is why you feel touch before pain. A giraffe's nerve impulses travel the same speed, but their brain takes longer to process signals from their feet due to the distance.
12. What is the most common mental health condition in the world?
- Depression
- Bipolar disorder
- Schizophrenia
- Anxiety disorders
About 301 million people worldwide suffer from anxiety disorders. Depression affects about 280 million. Together, they cost the global economy an estimated $1 trillion per year in lost productivity. Exercise has been shown in studies to be as effective as medication for mild to moderate depression.
13. What is the largest organ in the human body?
- The liver
- The lungs
- The skin
- The intestines
An adult's skin covers about 2 square metres and weighs around 3.6 kg. It replaces itself roughly every 27 days — you shed about 600,000 skin particles per hour. Over a lifetime, you will shed about 22 kg of skin. House dust is largely composed of dead skin cells.
14. What year did the World Health Organisation declare smallpox officially eradicated?
- 1970
- 1980
- 1975
- 1990
Smallpox is the only human disease to have been completely eradicated. It killed an estimated 300 million people in the 20th century alone before vaccination wiped it out. The last natural case occurred in Somalia in 1977. Samples of the virus are kept in only two laboratories — in the US and Russia.
15. How many steps per day are recommended for general health benefits?
- 7,500-8,000 (not necessarily 10,000)
- 5,000
- 10,000
- 7,500
The popular '10,000 steps' target originated from a 1965 Japanese marketing campaign for a pedometer called 'Manpo-kei' (10,000 steps meter). Modern research shows health benefits plateau around 7,500-8,000 steps. The key finding is that any increase in daily steps reduces mortality risk.