How to stop thread in C++ if atomic datatype was changed during thread sleep?

static std::atomic_bool lmb_down(false);
static std::atomic_bool rmb_down(false);

void do_work()
{
    for (int i = 0; i < 10; i++)
    {
        if (lmb_down.load() && rmb_down.load())
        {
            // DO SOMETHING
            std::this_thread::sleep_for(std::chrono::seconds(1));
        }
        else break;
    }
    return;
}

int main()
{
  MouseState state;
  while (get_mouse_button_event(&state))
  {
    switch (state)
    {
      case 1:
        lmb_down = true;
        break;
      case 2:
        lmb_down = false;
        break;
      case 3:
        rmb_down = true;
        break;
      case 4:
        rmb_down = false;
    }

    if (lmb_down.load() && rmb_down.load())
    {
      std::thread t1(do_work);
      std::detach();
    }
  }
  return 0;
}

What I want?

If both mouse buttons are pressed down then I want to start some work in another thread. If one or both mouse buttons were released then I want to stop all active worker threads.

What is the problem?

If mouse button was released and again pressed while worker thread was sleeping then do_work loop continues to do its work, but it should exit. (also another thread will be created, but that is desired)

How I tried to solve the problem?

I tried to use futures instead of global variables, but managing all the futures for new threads was too messy.