Hi! Thanks so much for your question!
 

It somewhat depends on what pre-reqs you have left to complete for your major/med school. For context, during my college career, I’ve taken calculus, statistics, physics 1 (+lab), and physics 2 (+lab) over the summer (each class was taken within its own semester).
 
One thing I’d recommend doing, if you haven’t already done so, is creating a four-year plan of what classes (or categories of classes) you’d like to take during each fall and winter until graduation, just to see if you’ll be able to fit in all of your pre-requisite classes within the fall or winter semesters. If you can fit all of them within the regular school year, then it isn’t necessary to take other classes within the spring/summer term, although you can do so if you’d like to lessen up your course load during the fall or winter.
 
In general, any summer or spring class, especially labs, can be pretty fast paced and time consuming, as compared to a fall or winter class, so I definitely think that having only one lab class during the summer would be a good choice. For this reason, I would not recommend taking either physics 1 or physics 2 (if these are classes you still have to complete), because it requires concurrent enrollment with its lab component. I think you could pair a lab class with another intro STEM class like Bio 171 or Bio 172 (whichever of the two you feel would be easier for you, which tends to be Bio 171 for a lot of students), a Chem class (depending on what Chem class it is and if it overlaps with the material of your lab), or a math class like calculus. 
 
I also think that it depends on how well you think you will understand the material from the lab class or from the pre-reqs you have left. If you feel that this class will not be your strong suit, then it may take more of your time and brain power than you may realize at first glance and you may want to take the lab class alone. Or maybe if you think that that lab class will be fine in terms of difficulty, and you only have your intro bio sequence left to complete, but bio is not your strong suit, then you may not want to take a bio class with the lab. As a result, your strengths may also factor into your decision of whether or not to add another class. 
 
I’d also like to mention, if you’d like to spread out your courses over the course of the summer, instead of taking both at the same time, is to take a lab class during one of the terms (spring or summer) and take another class in the other term, depending on what is being offered. Many pre-requisite classes are only offered during one of the terms (for instance, Bio 171 is only going to be offered in the summer term of 2022), so I would look into what terms each of your pre-reqs is being offered too. Again, this is not necessary, especially if you want to just study in the spring term and then relax for the rest of the summer or vice versa, but it is an option if you feel that it is necessary to take another class within the summer.
 
I also want to reiterate that it would definitely be fine to just take the lab class, and not any others, especially if you have other priorities during the summer, whether that be a job, volunteering, or just spending time relaxing with family and friends! What’s most important about the summer is making sure you have time to give yourself a break from all of the hard work you’ve been doing during the fall and winter :).
 
I hope this helps, and feel free to reach out with any further questions!
 
-Jasmine, PMH advisor