Short answer:
Anyone who tells you cardio is going to limit your gains to a meaningful degree either A) Likely doesn't actually know what they are talking about B) Probably doesn't actually do (read avoids) cardio anyways so their advice probably isn't that useful C) Is at a level of development advanced enough you’d probably know if you were there and not be worried about these types of things
Slightly more nuanced answer:
15-20 minutes before your session will likely only provide a negative effect if it is too intense or you are so out of shape (or both) that doing it limits your ability to perform high quality work in your lifting session (through various means of fatigue).
In which case you may find it beneficial to switch your cardio to after, move your cardio to another portion of the day, or just suck it up and accept slightly worse workouts with the goal of improving your cardiovascular fitness for better long term gains (especially if you are this out of shape it probably should have some focus in your plan).
Long answer everyone will skip:
A lot of this topic comes from misunderstandings of energy systems and older research that showed "potential" for interference.
More
recent research after more studies have been done tends to show
Therefore for most people who lift this really is a very small issue and probably not worth stressing over. Athletes with varying needs of explosive strength may need to keep training alterations in mind, but even most of them will still need it at various points in their training career/season, which is why smart programming is important.
If anything I'd make an argument, with a couple caveats at the end, that most people need more cardio and/or need to be in better shape if they want to make continual gains over a long training career.
Since most people probably didn't even make it this far I'll try to keep it brief for those who are still reading.
We see muscle capillarization may help with perfusion and that increases in capillary density may lead to larger increases in satellite cell content and hypertrophy versus low capillary density. Showing being in better shape before hypertrophy training may lead to larger gains (and is one of my hypothesis for why slower gains may be more sustainable or why certain individuals may struggle to maintain levels with faster approaches since increases in muscle capillary density and perfusion may be a slow). Studies
here and
here.
Now caveats:
Obviously (maybe not) this doesn't mean you can just do infinite cardio and infinite training and just act like it will be fine. The closer you are to upper limits/abilities, the harder either is taxing your recovery, and potentially other factors will impact the degree these things interact. For most people who are mostly focused on hypertrophy it probably still makes sense to:
1) Potentially limit the total amount done around a training session if cardiovascular benefits aren't the main goal.
2) Potentially split the sessions if your needs and recovery demand enough from both types of training.
3) Potentially have different focuses at specific times of the year understanding you may put some things slightly on the backburner in hopes of better long term outcomes.
But again that is why smart training is beneficial and most people who will tell you it is going to be a problem don't understand most of the above and probably don't actually do any of the above and finally most of the people worried about this probably are nowhere near the level they need to be to be that worried about it.
TLDR you are most likely fine and that amount shouldn’t be an issue.
, luckily thats not cardio
