• A person burns seven percent more calories if he or she walks on hard dirt than pavement.• A woman’s sense of smell is most sensitive during ovulation.• About 400 different kinds of microbes live on and in the human body.• About half of all Americans are on a diet on any given day.• Banging your head against a wall burns 150 calories per hour.• Flu shots only work about 70 percent of the time.• In an average lifetime a person inhales about 44 pounds of dust.