Probably both. Depends which way you came from as well. If you came from East (E.g.: London) then it’s pretty tough coming back and adjusting. I think the general rule is 0.5 day per time zone to adjust going east to west. 1-1.5 full days per time zone to adjust going west to east. I live in London and often go to CA for work. I can usually take on a lot of quality training in CA, but give myself an easy 1-1.5 weeks when I come back to London. Also, morning threshold workouts are terribly hard when I get back.

Given you didn’t do much running or biking, you gotta shake out the cobwebs and just get a routine back. Be consistent for 3 weeks, should be ok.

Thank you for the reply. I’m 6 hours east of Hawaii. I’ll stay consistent with the workouts and watch my HR. I’ll be far more diligent about getting in workouts, even when travelling. Fortunately my next race is only a sprint in late May.

For me after any kind of time off like this (where time off is at least a week), it takes me about 4-7 days to get back into the flow. That means that all workouts are at a lower intensity, and feel harder than they normally do. However, almost every time, I'm right back into the flow with the same fitness level within a week. Part of it is physical, and part of it is mental I believe.

I travel from the UK to America (Eastern USA or Eastern Canada) so 5 or 6 hrs difference depending where exactly I've gone to), historically a few times each year. Every time I come back to the UK (usually after 4-6 days away, on business) I'm ALWAYS wrecked for 5 or 6 days. I have a rule of thumb that if I land in the UK on a Saturday, its the following Thurs before I feel 'back to normal'. Training restarts (other than some very easy stuff) on the Friday.

I'm only away a few days, try to get at least some workout in, so its not a loss of fitness over that short period. Its the jetlag + lost sleep (inc the overnight flight back to the UK) for me.
It sucks !

Vacations are exhausting. You have to factor in travel, diet changes and no down time. You still did regular swim workouts. It all adds up. I agree that it will take a week or two to normalize. You do sound very OCD about your training (stress). You might want to cut yourself some slack and realize you were on vacation. A vacation is generally a break from everyday life...work, training, other commitments. It’s not like you were at a training camp.

Thanks everyone for the responses. It's reassuring to know that this is somewhat normal. I was concerned that I wiped out months of hard work with a couple of weeks off. When you're 62 years old gains are hard won.