For no reason should you take a loan to continue with margin trades in Bitcoin or whatsoever investment or business. To be frank it's more difficult to pay back money collected as loans to keep up your targets, moreso this why so many countries always remain in debts because they can't manage the little they have in generating more income rather they see it that when they take a loan it will boost the investment or business and generate more profits for them but they are getting it all wrong.
Taking loans for trading or gambling even if you believe there is a clear sign for you to make some money is always a bad idea because these are unpredictable things and you can't be sure of the outcome in both gambling and futures trading because your bet can always go against you and then you will be in big trouble if the money you had at stake was borrowed and has to be repaid with interest and now you have nothing left in your hands.
Those who are into futures trading do it with money that they own, and they know they can afford to lose it if a situation for that comes. Such things are also done only by experts, those who understand the market very well and they know that they won't make a lot of wrong decisions, and even if they do, they know they have enough back up to get themselves back up instead of losing control.