Try interpolation!
doc interp1
Here is an example using "interp1" with the method set to "spline":
T = 60*8; % max time = 480 minutes (= 8 hours)
t = 0:5:T; % uniform time across T every 5 minutes
t_rand = sort(rand(1,T)*T); % irregular time across T at random sample intervals
data = @(t)sin(2*pi*0.03*t) + cos(2*pi*0.1*t) + sin(2*pi*0.05*t) + 2*sin(2*pi*0.005*t) ;
data_interp = interp1(t_rand,data(t_rand),t,'spline');
plot(t,data(t),t_rand,data(t_rand),t,data_interp);
legend('Uniform time','Random time', 'Interp time');