Comfortable 10k or flat-out 2,5k intervals?

[Sandeman]

I've been using my RowErg for about a year now. After building up my technique and stamina a bit I usually do one session a week now and in that session I usually try to do 10 km or 1 hour of rowing. As fast as I can without burning out during the session.
So no real high power or high speed stuff. I have a weak back and some other annoying problems, so I try to keep myself injury free

But yesterday I was motivated to do something else and I did 500m intervals with 2 minutes rest.
I went full out and after 5 intervals (2500m) I felt like I was falling apart

Arms were burning, I felt my legs getting tired (which I usually never feel), heartrates were near maximum, etc.

It was fun for a change, but now I wonder what is better for me...?
Doing a relatively comfortable 10k or 2,5k flat out..?

The PM says I burned a lot more calories in the 10k session, but I felt WAY more tired after the 2,5k interval session yesterday.
And I can imagine the 2,5k session being a lot better for building muscles and for the cardio system...? So maybe better in the long run?

I started rowing to improve my general fitness (I'm a lazy person) and to loose some weight. I don't have any ambition (nor the capability haha) to be an ultrafast rower or to do competitions.

So overall... What's the best way for me to workout?

[RayOfSunshine]

Given you only row once a week, I can't believe there would be a significant difference in which is better for you.

Why not just do which one you enjoy the most or mix them up? It sounds like you enjoyed the change. Perhaps you'd want to try 2-3x per week if you found yourself really enjoying the erg.

[Tobias Stoehr]

Why not do both. Mix it up.

[Sakly]

+1 - mix it up.
To gain more fitness you should do both per week, so row at least twice a week. You are not getting faster, because the breaks between your rows are too long and your adaptions are already gone, when you row again.
The intervals build different energy systems and have a different load on your muscles compared to the long slower rows - you already know how different it feels.

[Sandeman]

Ok, I'll try to mix it up. I find it hard to motivate myself to get on the tower after a long day at work, but I will try to do both in one week. See what happens. Thnx for the advices!

[p_b82]

I think the answer to the question is "it depends"

if calorie consumption is a major factor, then longer seat time is going to trump shorter intervals - but if it's just once a week, then it's not going to make "that" much difference.

An so on that note I'd say do 1x hard session a week regardless of whether it's intervals or a distance/time; in my experience a hard 10k was tougher to complete than a hard 2k; even though my body recovered quicker from the former.

When I swam previously, I only did that once a week, and I compromised; did a 100% effort 1500m. I switched to it from an hour's gentle swimming as I wasn't feeling that I'd done much work at the slower pace, and needed to get my HR up more and feel the fatigue in my muscles. Brought my time down from 45mins to 30mins, but the progress was gradual due to the low frequency.

Ultimately doing what you can sustain and you enjoy is more important, and so if that's one slow hour long row a week with the odd interval session then that's all it needs to be

[jamesg]

So overall... What's the best way for me to workout?

As often as possible with a good stroke, keeping the work hard but low rate and with short pieces after a good warmup; typical 1k intervals.

Keep tabs on quality, which at your size and age means at least 200W at rate 20.

Lose 20kg.

Target 1: 5k in max 20 minutes, rate 22 max.
Target 2: 2k 7 minutes rate 28 max.

[Willy.VdW]

I find it hard to motivate myself to get on the tower after a long day at work,

Getting started can be really difficult when you are tired, but maybe you will feel "reborn" after (a short interval?) workout