Maybe after too little sleep at least you notice you feel bad, whereas without any sleep you don't even notice anymore. If your memory doesn't function right it's no surprise that your temporal perception inherently relying on memory would be impeded. Since the hormonal system is rather complex, enthusiasm can be a byproduct of trying to stay awake. Likewise, the sport mentioned in the OP is at least as likely to cause happiness, not to say that I doubt the headline altogether.