When you connect your Garmin account to REN, we don’t just sync your future runs — we also look back.
REN automatically pulls in (or “backfills”) your last 30 days of activities from Garmin. This gives REN a real-world snapshot of what you’ve actually been doing recently, so your training plan starts from you, not from a generic template.
Here’s how that works, and what it means for your first weeks of training.
What happens when I connect Garmin to REN?
Once you connect Garmin:
REN imports your past 30 days of activities
It combines that history with your onboarding information (goals, experience, frequency, etc.)
Based on this, REN estimates a safe starting load and builds your plan from there
So if you’ve been consistently active in the last month, REN will see that and start at a level that matches your recent training.
Why does REN look at the last 30 days?
The last month is a strong indicator of your current, real-world capacity:
How often you’ve been running
How long your typical sessions are
How much your body is used to right now
Instead of guessing, REN uses those 30 days to:
Avoid jumping you into too much, too soon
Avoid starting way harder than your current fitness
Build a plan that respects your recent training load
What if I haven’t done much in the last 30 days?
This is important to be aware of.
If your last 30 days on Garmin are:
Very light
Inconsistent
Or almost empty (e.g. break, illness, holiday, injury)
…then REN will protect you by starting more gently than you might expect.
That can mean:
Shorter runs
Fewer intense sessions
A “slower” build-up than what you feel you can handle
It might feel like REN is underestimating you — but from the app’s perspective, it’s simply reacting to the data it sees: a quiet month.
Can I make REN speed up the build-up?
Yes. REN adapts quickly when it sees that you can comfortably handle more.
If the early weeks feel too easy, and you’re confident that your true capacity is higher than what the last 30 days show, you can:
Do a bit more than prescribed in the first weeks
Slightly extend some easy runs
Or add a little extra low-intensity volume (not all-out efforts)
When REN sees consistent completion of slightly higher load without issues, it will start to build up faster and adjust your future training to match.
💡 The key idea:
Your recent data teaches REN who you are. If the 30-day backfill painted you as “very inactive,” but you safely show that you can do more, REN will catch up.
Important: Don’t overdo it
While REN can adapt quickly, your body still needs time.
Only do more than prescribed if you are sure you can handle it
Increase gradually, not by doubling everything overnight
Listen to warning signs like persistent soreness, pain, or heavy fatigue
If you’re unsure whether you should add more:
It’s perfectly fine — and often smart — to follow REN’s plan exactly
A conservative start is much better than getting injured in week one
What if the 30-day backfill doesn’t reflect my true level?
Maybe you’re:
A strong runner coming back from a short break
Someone with years of experience but a quiet month
Or you’ve just switched devices and only have partial data in Garmin
That’s okay.
Even if the 30 days from Garmin don’t give a perfect picture of your physical capabilities:
REN will start cautiously based on those 30 days + onboarding
As you train and log/sync your workouts, REN will update quickly
Within the first weeks, your actual training will matter more than that initial snapshot
In short
Connecting Garmin lets REN backfill your last 30 days of activity
Your starting point is based on those 30 days + your onboarding info
If the past month was quiet, REN may start slower than you expect — be mindful of that
Doing a bit more (safely) in the first weeks can help REN ramp up faster
Most importantly, REN will adapt quickly, even if the 30-day backfill didn’t fully capture what you’re really capable of
Trust the process, listen to your body, and let REN adjust to the real you as you go.