HaLong Bay

Not a bad view to wake up to. This is a beautiful part of the world. Today was a day involving kayaking, visiting an island village and ( for Martin) some cycling too. The kayaking was harder than expected. Was this due to
1. the everlasting jet lag?
2. the after effects of a back, neck and shoulder massage the night before?
3. the poor timing of one of the kayakers( there were two of us in a kayak) ?
4. All of the above?