how your morning cup of coffee affects you depends on what else you have along with it. Take nicotine. Caffeine drinkers are more likely to smoke cigarettes. And that makes sense since surveys show that caffeine makes cigarettes more appealing. But there's evidence that combining the two can have gnarly side effects. If you smoke a cigarette, the caffeine from your morning coffee hypes up nicotine's effects and can make you way more likely to have a heart attack than either would alone. That's likely because caffeine and nicotine together makes your heart stiffer. and heart stiffness is something doctors look for when diagnosing cardiovascular disease. So a stiffer heart is related to serious health problems like heart attacks. One study even found multiple signs of heat stiffness after caffeine and nicotine use in young, seemingly healthy people that aren't the usual heart attack crowd. Which makes caffeine and nicotine more problematic together than apart.