High latency when uploading - fibre

[#1]

Hi
Recently I have started noticing that whenever our internet connection is being used to upload (video, twitch, large files) that the latency spikes massively.
There is no drop in download speed but the ping increases by around 150
Example
BEFORE:
<a href="http://www.speedtest.net/my-result/3614282290"><img src="http://www.speedtest.net/result/3614282290.png" /></a>
WHEN UPLOADING:
<a href="http://www.speedtest.net/my-result/3614276345"><img src="http://www.speedtest.net/result/3614276345.png" /></a>
Any reason for this?
On FTTC by the way

[#2]

Yes, you're uploading. That's why you have a high latency.

[#3]

but this didn't use to be the case? only started happening recently

[#4]

It depends how much of your upstream you're utilising. If you're pretty much maxing out your upload, it'll cause high latency. If you're using your upload on P2P software, there is usually a way that you can cap how much of your upstream is being used.

[#5]

Oh right I see. Is this just a case of not noticing it before? I upload to twitch and youtube mostly and these to tend to max out my upload.
Whats the technical reason behind higher pings? (just interested)

[#6]

I'm trying to find the best way to explain how this works...
I found this explanation quite a good one http://superuser.com/a/701238

[#7]

ah that does make sense. Guess I have just never noticed it before!
Thanks for the link