It's no joke that gym equipment is teeming with bacteria, and many of these germs can lead to all kinds of infections. And it's not just treadmill and exercise bikes, but dumbbells and barbells, too. Along with all the pesky bacteria, cold and flu viruses can live on hard surfaces (like stainless steel or hard plastic) for up to 24 hours. We definitely don't want you to stop working out — after all, regular exercise is great for the immune system — but there are some very, very easy ways to keep all those germs at bay.