Boners are all about blood flow. So your heart—the organ that pumps your blood—has to be in tip-top shape for you to have A-plus erections. Anything that puts strain on your ticker, like being overweight or smoking, also tends to take lead out of your pencil.
Testosterone is the second factor that’s crucial to a strong erection, and there are plenty of weird things that screw with its production. All the items on this list can mess with your manhood:
1. Grocery receipts. The types of thermal paper and ink used for most supermarket receipts contain high levels of bisphenol-A (BPA), a chemical that increases your body’s production of the female hormone estrogen. And that estrogen boost—along with some other BPA-triggered hormonal changes—harms your hardness, finds a study from Kaiser Permanente. ATM receipts, airport baggage tags, and lottery tickets are all printed on this BPA-heavy kind of paper. As you’ have probably heard before, hard plastics and canned foods are also common BPA sources.
2. Dessert. Consuming sugar, whether in a slice of cake or a can of soda, causes an up-tick in your blood’s glucose levels, which stimulates the release of the hormone insulin. That torpedoes your body’s testosterone production, making it tougher for you to get it up, shows a study from Irish and American researchers. (This sugar-insulin-testosterone connection also explains why your T levels spike and you tend to pitch a tent first thing in the morning—when you haven’t eaten for hours.)
3. Crappy shuteye. Sleeping 5 hours a night (or less) for a few days was enough to sink T levels by 10 percent among a small group of healthy young guys, found a study from the University of Chicago. Sleep is essential for testosterone production. And so if you’re not getting enough of it—around 8 hours a night—don’t be surprised if you erection seems groggy, the study suggests.
4. A baby in your bedroom. Snoozing in close proximity to your newborn—like if you have him or her in a bassinet in your bedroom—lowers your testosterone production 7 percent or more, shows a study from Notre Dame and Northwestern University. You might think sleep disruption is to blame. But there’s evidence that hormonal shifts caused by spending the night next to your tyke triggers the drop in T, the study authors say.
5. Soy. Every vegan’s favorite meal ingredient has “estrogen-like properties” that saps your body’s T store, finds a study from Harvard Medical School. A little soy won’t kill your libido. But a soy-heavy diet—think multiple daily meals that include it— could spell trouble for your erection, the study demonstrates.
6. Spending time indoors. Vitamin D plays an important role in testosterone production. Fail to get enough D from sun exposure or your diet, and your body’s T levels can plummet by 20 percent or more, shows research from Germany and Austria. (On the bright side: Just 15 minutes of midday sunlight on your bare arms and legs is enough to get your daily D dose, advises a report from Harvard Medical School.)
7. Pounding (too much) pavement. Running 40 or more miles each week could drop your T levels by 17 percent, suggests research from the University of British Columbia. Too much running could disrupt communication between your brain and hormone-producing glands, which might explain the T drop-off among hardcore runners, the authors say.
8. Booze. Noooo! You were probably praying alcohol wouldn’t pop up on this list. But multiple components of your drink of choice—from the hops in beer to the congeners in wine and liquor—infuse your libation with “estrogen-like substances” that appear to lower your testosterone, shows a study from the University of Oklahoma. Fortunately, you need to drink a lot—probably more than two drinks a day—to experience a slump in your winner, explains resources from the University of Wiscons