I just started weightlifting a couple of weeks ago. Right now, I'm deadlifting 65 lbs for 3 sets of 15. When I'm done deadlifting, I usually breathe heavily and have a high heart rate, like I had just sprinted for a couple minutes. Is this normal for weightlifting?
It's impossible to say nothing's wrong with you. I'm not a doctor. If you have medical concerns, see a doctor.
But that aside, I would say it is normal to be out of breath after a hard set of any compound lift. Heavy squats (for 5 reps) almost always leave me feeling somewhere between out of breath and about to pass out.
There are things that can make post-set exhaustion worse, like low blood glucose, dehydration, or electrolyte imbalance. So make sure you're eating enough carbs, staying hydrated, and getting enough sodium/potassium/calcium. And like Dave Liepmann said, make sure you're breathing. That sounds obvious, but it's instinctive to hold your breath when you're straining and it's easy not to notice.
If you know your diets good then you should be fine. Running out of breath on deadlifts are normal. I powerlift and after a warm up set on my Deadlift I breath heavier an heart rate increases. Then after a max set my heart rate is beating out of my chest and I'm breathing very heavy. And I'm in light weight class so I do some cardio to keep of some extra lbs.
it seems normal, but as you stated you are doing this for couple months I am asuming you were using lower weights before.
To soothe your problem try doing some breath exercise which will increase your capacity to breath more calmly in these situations.
Plus also, please don't over lift or over rep anything if you feel that you really feeling breathless try decreasing your sets as you already stated you are only doing this to be in good shape, or you can also try increasing the rest time in between each set.
When you try lift something heavier especially in a sequence your veins and your muscles get full pull it's a common human body reaction when lifting something heavier your lungs and mind tend to hold breath to give your body maximum capable power as if you were breathing out it will result in relaxing that decreased the body power.
The solution for this is by lifting weight that your body can easily handle so you can breath in and out but do it fast so you can maintain the power.
It is same like throwing a punch, when you are angry you - first you take your punch back holding your breath and then release it to the opponent to produce maximum damage and releasing the breath.
This kind of reactions can make your heart beat faster and make you breathless in couple of shots, leaving you immobilize to think that I can run more than 1 - 2 km without any difficulties "but why I become breathless so fast with few punch ?"
The answer is simple you ask your body to provide you maximum power possible, your body reacts to your command and start burning even the single oxygen taken in the lungs and to process energy your heart start pumping at the max possible rate "Providing you maximum power possible sacrificing breath and heart beat rate"
Hope that answer your Question.