When would you say you do your clearest thinking? Mornings feel like a struggle for many of us – but a new study shows that when it comes to replying to emails, that’s when people are most on top of their game.

The study, by the University of Southern California and labs belonging to search engine Yahoo, examined no fewer than 16bn emails from two million people.

It turns out we send the longest, most considered responses before lunch. After that, our replies get shorter – and as ‘email overload’ builds up through the day, we reply faster, but to fewer emails.

That’s important information when your success relies on getting the right message to the right people – at exactly the right time.

We already know that social media is strongly time-sensitive (research shows Facebook usage peaks on weekdays at 11am, 3pm and 8pm, and is lowest on Sundays). That informs our posting so we make sure we’re reaching the people we want to reach.

Now we know email is equally sensitive to our daily rhythms, which is probably not really a surprise to anyone who’s ever faced an over-full email basket in the afternoon.

However, it’s crucial knowledge to Cool Blue, because direct marketing and email marketing are useful tools of our trade.

For instance, in our continuing campaign for Go Digital Newcastle, we’ve used email carefully and successfully to reach thousands of SMEs in the city and let them know about the free superfast broadband connection vouchers that are available (www.godigitalnewcastle.co.uk).

Now – more than ever – we’ve got our eye on the clock…After all, a message unread really isn’t a message, is it?