When You Drink Coffee Matters

Many people like to begin their day with a cup of coffee. For some, that is all they need. Others will continue to consume the popular beverage throughout the day. Are there risks with doing so? Should you limit yourself to coffee only in the morning? One doctor shares his advice about the timing of coffee consumption, and a recent study linking morning coffee consumption to lower death rates from cardiovascular problems and reduced rates of all-cause mortality risk:

Texas Health Fort Worth cardiologist Dr. Sreenivas Gudimetla offers some possible reasons why the timing matters:

First, there's a substance produced by the body called adenosine. It promotes sleepiness. And this substance builds up throughout the day. When you drink coffee in the morning, coffee with caffeine counteracts it (adenosine) so that you will be much more alert during the morning.

However, in the afternoon and evening with the stimulant effects of coffee, adenosine will delay your body's natural sleep-wake cycle and disrupt your circadian rhythm. And so, if you drink coffee in the afternoon, it could disrupt your sleep patterns, which could potentially have an adverse cardiac effect.

Another potential mechanism is that heavy coffee consumption in the afternoons and evenings is associated with a 30% decrease in peak melatonin production. Melatonin increases oxidative stress levels, which raises blood pressure and increases CVD risk.

This study doesn't seem to make a difference, though, whether it's moderate coffee drinking or heavy coffee drinking. 

I do find that interesting because in prior studies there was a difference. Heavy coffee drinking - more than five to six cups per day, for instance - can elevate heart rates, increase blood pressure and, in sensitive people, may increase the risk of arrhythmias.

Most people who have heart arrhythmias, such as supraventricular tachycardia - which is like a short circuit in your heart that causes your heart to beat fast - or atrial fibrillation, can tolerate drinking moderate amounts of coffee without any real adverse effect. But some are sensitive to that.

If you don't drink coffee, is it a good idea to start? 

I wouldn't go that far necessarily. This study, like other studies published regarding coffee consumption, is a retrospective observational study. They’re self-reported. People use their recall to tell when they drink their coffee. So, we can't verify whether it's 100% accurate.

Also, there are measurement errors and things like that. So, we have to take that into account. I think it's safe to say that there is an association, but I don't think it's safe to say that there's a cause and effect.

The other thing to consider in all this is that there are other variables besides coffee in coffee drinkers that can potentially result in a cardiovascular benefit. For instance, when people wake up early and drink coffee, they tend to have a healthy lifestyle, are more willing to exercise, and eat more non-ultra-processed foods. So, there could be a lot of other confounding variables that should tell us that we probably should not make a blanket recommendation that people who don't drink coffee should drink coffee for cardiovascular benefit.

You can read the full article here.

Of course, the results of one study do not mean you need to change your habits. For every study out there, you are likely to find another that directly contradicts what it says. The best approach is to look at the overall body of research, and follow guidelines set by medical professionals.