I know it is not unknown for people with this horrible disease to grow extremely tired - but I am just wondering if anybody has experienced anything similar to this. My husband generally does well sleep-wise - generally he will be until almost 11pm and does not tend to nap during the day. There have been a couple of occasions recently though when I have thought he was about to collapse through exhaustion - it's like he has momentarily fallen asleep on his feet, and it is the sensation of falling over that has made him wake up - to the point where he suddenly sways and staggers in a bid to stay upright. On both occasions so far, this has followed long, tiring days and a fair bit of travelling on the trains and underground - so I know the reason behind the exhaustion. It is just a bit disconcerting how suddenly the tiredness sweeps over him - one minute he can be enjoying everything, the next second, it is like someone has flipped a switch and he almost drops down where he is.