how to draw vertical lines on the plot?

Hello, I'm doing HRV spectral analysis and I want draw vertical lines around freq bands on my plot. It'd be great if each area could be in different colour. If anyone could give me any tip, shall be very grateful ;)

I need to add this to this plot:

%Calculate PSD
    [PSD,F] = pwelch(odstepRR,128,64,[],fs); %uses a hamming window

      VLF = [0.0033 0.04];
      LF = [0.04 0.15];
      HF = [0.15 0.4];

      % find the indexes corresponding to the VLF, LF, and HF bands
      iVLF= (F>=VLF(1)) & (F<=VLF(2));
      iLF = (F>=LF(1)) & (F<=LF(2));
      iHF = (F>=HF(1)) & (F<=HF(2));

      % calculate areas, within the freq bands (ms^2)
      aVLF=trapz(F(iVLF),PSD(iVLF));
      set(handles.vlf, 'string', num2str(aVLF));
      aLF=trapz(F(iLF),PSD(iLF));
      set(handles.lf, 'string', num2str(LF));
      aHF=trapz(F(iHF),PSD(iHF));
      set(handles.hf, 'string', num2str(aHF));
      aTotal=aVLF+aLF+aHF;
      set(handles.tp, 'string', num2str(aTotal));

      %calculate LF/HF ratio
      lfhf =aLF/aHF;

axes(handles.axes5);
set(handles.text45, 'visible', 'on')
set(handles.axes5, 'visible', 'on')

%plot area under PSD curve
area(F(:),PSD(:),'FaceColor',[.6 .6 .6]);        

grid on;

Answer 1

[Walter Roberson]

line([X X], [LowY HighY])

for example,

line([5 5], [0.1 17])

to draw a line from (5,0.1) to (5,17)

[Safwaan Kraft]

thanks this help. :)