So, my sister-in-law asked me a few months ago what she should do for her low back pain.  She did not know if it was muscular or vertebrogenic low back pain.  This means that it is either from the muscles or the spine.  She said that she had already been resting in bed for the past week and using a heating pad. I wasn’t quite sure how to respond. First, I felt embarrassed because I somehow expect that all of my family will automatically know the right course of action for injury just because we are related. Second, I felt awkward because lying in bed probably set her recovery back a significant amount of time and the heating pad may have increased the swelling and inflammation.
I have been a physical therapist since 2009 and never in my years of practice or while earning my doctorate did I ever learn to use bed rest to treat low back pain. This is a treatment that is out of date and is not substantiated by the research. I will admit, however, that it is persistent. Even my mom tells me that I need to lie down if I mention my back hurts. That is also embarrassing.
So what should my sister in law have done?
The most absolute, correct answer is… it depends. It depends on what she injured in her back. However it was most likely one of two things. My sister in law has two small children, ages 1 and 3, and has to bend over and pick up small, wriggly but heavy kids a lot. She either strained (tore) a muscle in her low back or sprained (tore) a ligament in the low back. There is also the possibility that a joint along her low back became irritated and stuck. However these all have the same treatments (mostly). Number one, go see your friendly, local physical therapist. You will probably be better in a week or two. Number two, move!
How to treat acute low back pain
So once you realized that you hurt your back, it could be suddenly or the pain could come on gradually, you need to keep moving. Now, I am not asking you to put yourself in excruciating pain but I am telling you to keep doing all the things that do not increase your back pain. This might include walking, cooking, 
throwing fetch with the dog, etc. If it doesn’t increase your pain, then do it. This keeps the area of injury warm, the blood flowing to the area, and keeps your spine moving so it does not get tight and actually hurt more. It also prevents stiffness and strength loss from occurring in other areas of the body that are not injured.
So how do you know if an activity increases your pain? Let’s use walking for an example. If you begin walking with no pain and then start having pain that continues to increase, it is a good bet that walking is exacerbating your pain. However if you have mild pain that actually improves as you walk, then walking is probably good for your injury.
When you rest in bed, the area does not move and gets very stiff because of the inflammation. This causes even more pain when you get up to move again. In fact, when I have had low back pain, some of the worst pain has come after sleeping because my spine has not moved much during the night. After I get up and move around, it feels much better. Also extended periods of bed rest can cause a significant decrease in muscle strength. It only takes a week of bed rest to have a significant loss in muscle mass.
Also I would usually recommend ice initially after an injury including a low back injury. Heating the area is not going to do anything really bad but it might exacerbate the pain briefly by bringing in more fluid to the injury site. So I usually don’t recommend heating for the first 2 or 3 days after an injury. After the initial few days, you can heat when needed which is usually for comfort or to bring blood flow to the area to decrease stiffness. Ice acts as an analgesic and an anti-inflammatory. In other words, it decreases pain and reduces inflammation and swelling. Ice several times per day for about 20 minute at a time (in between periods of moving around and being active) and continue to ice daily while still having pain. Make sure to have a thin layer of cloth in between your skin and the ice pack. A pillow case works great for this purpose. My family always has a couple of gel ice packs in the freezer at all times – just in case somebody gets injured.
Now with most low back pain, a certain movement will usually hurt more than other movements. This could be bending forward, bending back, or twisting. Sometimes if you repeatedly move in this directions, it will help relieve the pain. Sometimes it won’t. This is where your local, friendly physical therapist steps in. They will evaluate what is actually causing the pain and develop a plan of care to treat it. This is one of the reasons why it is nice to have a physical therapist (like a primary care physician) that you know and trust. I have many patients that I have seen multiple times. They come in soon after an injury, like low back pain, and are usually discharged in 2 to 3 weeks pain-free because the problem was addressed so quickly.
There are a few exercises I give patients with most types of low back pain just to keep motion in the low back. These might cause some soreness with the first few repetitions which is normal but should decrease in soreness after several repetitions and feel better after completing the full exercise. This can be true of other activities as well, including walking. Walking is actually one of the best exercises for low back pain because it does not put much stress on the back but it increases blood flow and gives some good aerobic activity. You might feel sore with the first few minutes of walking but then it gradually improves as you warm up. As long as you do not get increased pain during an activity or after the activity, it will not increase your low back pain. See the video below for some gentle low back exercises.
In review
So, when you have low back pain, whether sudden onset or gradual:
- Schedule an appointment with your physical therapist
- Use ice to help control inflammation and pain. You can use heat on day 3 or 4.
- Move and perform your normal activities as long as they do not increase your pain.
Additional resources
https://www.choosept.com/health-tips/5-common-myths-low-back-pain