@BillOddie – it’s the only thing I can do with my limited time at the moment!
You sure?
You’ve not said what equipment you have at the gym but I bet you have a rower there!
I’m going to assume you have…
Intervals on the rower (tons of HIIT protocols online) or a good old fashioned 2km row for time (if you don’t want to die/quit at the 1km mark you’re not trying hard enough).
If you split your time 50/50 weights and cardio you can get a decent squat, deadlift, press or barbell row session (bonus points for doing a press and a barbell row supersetted) in the 1st 20min and then give yourself a horrible CV workout in the 2nd 20mins.
But if you haven’t got a rower
5+ rounds of a circuit of goblet squats, DB bench, DB Rows, KB Swings, Overhead DB Press then 1min rest will get your Heart Rate up and give some strength gains at least initially (assumes you are untrained at this point).