Lossen up your straps. Mine still go a little dumb, but I just curl them up a little to get the blood flowing again, but usually it's shoes are too tight.

Either your shoes are too tight or you need shoes with a stiffer sole. I would say that if you are riding with running shoes, you should look into getting a pair of cycling shoes. If you already have cycling shoes and you are having this problem, you need to loosen the straps of the shoes.

My toes were going numb for the longest time and I couldn't figure out why. A cyclist with a lot of experience told me to get larger cycle shoes and wider pedals. I went from a standard SPD pedal/cleat system, to Look pedal/cleat. I also ordered Triathlon shoes by Lake. They have one big velcro strap that I can easily adjust while on the bike if I have numbness. The wider pedal helped alieviate pressure on the ball of my foot, resulting in numb-free rides. Also, having shoes that are larger gives me wiggle room for my toes.